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The technique of Fourier transform infrared reflection-absorption (FTIR-RA) spectroscopy has been successfully adapted to the study of bulk and interfacially activated photodegradation of several types of polymers on various metallic substrates. The technique enables qualitative and quantitative study of photochemical reaction mechanisms and rates. A controlled Environmental Exposure Chamber (CEEC), which permits collection of IR-RA spectra of the polymer/metal samples during their exposure to controlled spectral distributions of UV, temperatures, and gas mixtures, was built into the sample compartment of a Nicolet 7199 FTIR spectrophotometer. Surface analysis, gel permeation chromatography (GPC), UV spectroscopy, and UV spectroradiometry were used to complement the FTIR-RA results.

One of the possible solutions for improving mirrors for long-life, inexpensive solar concentrators is to coat the reactive mirror material with a polymer. Polymer-coated reflectors may improve optical efficiency and reduce the cost of solar mirrors. Because the mirror/polymer interface may have long-term instabilities in a solar-stressed environment, it is necessary to isolate the effects attributable to the bulk materials from those of the interface. Actual failure mechanisms are unknown but we present several possible explanations for failure of the polymer/mirror interface. The purpose of the paper is to review the literature on one of the systems of great current interest, the silver/polymer interface. First, the components of this interface are considered separately. Studies of reactions of environmental gases with silver are summarized. Then, several candidate fluoropolymers and polymethylmethacrylate are considered independently of the metal. The thermal, photo, and oxidative degradation reactions are briefly outlined. Finally, the limited data actually obtained on the silver/polymer interface are summarized. Results obtained on the silver/Teflon-FEP interface are emphasized because its use for thermal control panels in the space program resulted in extensive study. 117 references.

The scattered ion yield from polycrystalline Ag, Al, Au, Cd, Co, Cr, Cu, Fe, In, Mo, Ni, Pd, Si, Sn, Ta, and W foils has been measured for 0.2, 0.5, 1.0, 1.5, and 2.0 keV incident helium neutrals (NSS) or ions (ISS). Measurable scattered helium ion spectra in NSS, which were obtained for all sixteen elements from 1, 1.5, and 2 keV incident neutral helium, consisted of two peaks, I S and I B , from surface and subsurface scattering, respectively. In all cases, E / E 0 for I S is 25 eV (the ionization energy for He), below that for a single binary elastic collision (SBEC). The intensity of I B depends strongly on the element bombarded; it is smallest for Ag, Au, and In and largest for Cr, Mo, Ta, and W. The ISS spectra yielded peak positions that varied from 0 to 30 eV below that for a SBEC. The low energy tails of the spectra consist of ion yields from scattered ions and reionized neutrals. The energy dependence of the shape of these low energy tails results from the relative fractions of scattered ions and reionized neutrals, where the relative fractions are strongly material dependent.

A short course taught intensively for one, two, or five days is the most important of several media used by the Education Committee of the AVS to disseminate educational material about subjects of interest to the Society. The historical development of short courses is traced from offering one course to 80 registrants in 1969 to an availability of 29 courses that were taught to over 1200 persons in 1981. For these 12 years, data are given for the course titles, year(s) offered, number of registrants for each course taught, and location of the short courses. The number of registrants and short courses offered by local Chapters and Divisions are given for 1979–1981, and the cosponsorship role played by the Education Committee to assist Chapters is outlined. The course offerings demonstrate a responsiveness to the needs of the membership, Chapters, and Divisions of the AVS as well as the vacuum industry at large. Since mid‐1978, 400 of the 1300 new members of the Society have been gained directly from the short course program. Future plans and prospects for service to the AVS membership and the scientific and technological community‐at‐large are outlined, especially the possibility of video taped courses. The importance of maintaining a strong set of short course offerings for the local Chapters and Divisions as well as the AVS as a Society is included in the discussion.

Bilayers of Ag/Cu or Cu/Ag have been vacuum deposited in situ onto cleaned quartz, Si(100), and copper substrates at thicknesses from 20 to 50 nm, as measured with a quartz crystal oscillator. Depth profiles on the same samples were obtained using neon bombardment and either ion scattering spectroscopy (ISS) or Auger electron spectroscopy (AES) for compositional analysis. Profiles were taken after deposition at 30 °C and then after heating up to 300 °C, all in situ at about 20 nPa. Interdiffusion was detectable at 100 °C for both Ag/Cu and Cu/Ag bilayers, but differences were found in the extent of the diffusion. Dramatic differences were found in ISS and AES profiles of bilayers on silica and copper substrates. The differences are attributed to electron beam effects that result in profiles similar to those induced by thermal treatments at much higher temperatures. Reasons why the ISS profiles better represent the true in‐depth composition are given.

An all quartz pivotal‐beam ultramicrobalance has been modified for operation as a null instrument using a dual‐path photoelectric detector. The beam and newly designed stainless steel beam support have been adapted to a stainless steel enclosure for studies in uhv. A thin quartz disk, with a 600‐A thick Au film for partially blocking the light path, is fused to each end of the beam. An electronic circuit minimizes the signal from the detector when the balance moves from the null by providing a current output to a magnetic compensation coil. The capacity (up to 20 g), the stability of the null reading (over six months), and the unusually high load to precision ratio (1–2×108) of the balance have been maintained with the modification. Sensibilities of 0.03–0.1 μg with 4–10‐g loads have been obtained with the balance, which is now completely adapted for UHV operation.

An experimental approach to the study of polymer film photodegradation by Fourier transform infrared (FT-IR) spectroscopy, simultaneous with UV irradiation under varying thermal and environmental stresses, is described. Reflection spectra collected from polycarbonate-glazed gold mirrors undergoing irradiation in an environmental test chamber are presented as examples of the system's capability. The early degradative events in polycarbonate can be deduced from differences in these spectra.

Up to one monolayer of Ag on high purity fused silica has been investigated using XPS and ISS. A Sn sensitizing complex and then Ag were deposited onto silica using a wet chemical electroless process. The XPS data indicated that Sn is bound to Si after sensitization with SnCl – 3 , and 30% of the surface Si is covered with the Sn complex. Using ISS it was determined that Sn is a surface species only, and corroborating evidence for 30% coverage of Si surface sites was found. After silvering without the reducers normally used, XPS showed that 60% of the surface Si is bound to Ag, while 20% of the surface Si sites remain covered by a Sn complex. ISS again verified that Ag is a surface species and indicated that more Si than O is shadowed by the metal atoms.

IR specular reflectance spectra with respect to hydrogen peroxide formation during uncatalyzed and Cu (oxide)-catalyzed oxidation of isotactic Polypropylene films have been measured as function of time and temperature (90–130°C). Energies of activation for the various cases have been obtained. The originally proposed kinetic scheme based on oxygen-absorption measurements has been modified in order to accommodate the spectroscopical results. The amount of ROOH groups present at any time on the polymer is very small, indicating relatively slow rates of ROOH formation and fast rates of their decomposition. The kinetic scheme fits well the experimental data. However, the reasons for the variations of the relevant energies of activation obtained for the catalyzed oxidation in absence and presence of the main volatile reaction products, H2O and CO2, are not yet understood, i.e., the mechanism needs further investigations.

Silver mirrors, made by decomposing organometallic resinate solutions, have been studied using surface analysis techniques to secure information about the silver/glass interface. The mirrors have also been characterized using SEM, EDAX, thickness, reflectance, resistivity, accelerated corrosion testing and adhesion measurements. The mirrors exhibit excellent adhesion at the silver/glass interface and good corrosion resistance. Depth profiles using XPS, ISS and SIMS for analysis have been taken in the mirrors. From these studies, evidence for an increased silicon to oxygen ratio at the silver/glass interface is presented. In the silvering process, it is thought that the silver-containing Lewis base decomposes when in contact with glass at elevated temperatures (T > 400°C) to deplete the glass of surface oxygen, or silicon from the resinate deposits to enrich the glass surface. It is suspected that covalent silver to silicon bonds are formed during decomposition of the organometallic solution and reaction with the silicon rich glass surface and that these bonds are responsible for the excellent adhesion and thus, good corrosion resistance of the mirrors.

Thin Ag films of up to one monolayer on high purity fused silica have been investigated using variable angle x‐ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS). Silvered samples were prepared using the wet chemical process without reducers or by vacuum evaporation. After sensitization with a tin complex, it was determined from ISS that Sn is a surface species only and covers up to 30% of Si surface sites. Variable angle XPS verified these findings and suggested that the Sn is located above the Si surface plane. After silvering with the wet chemical process so that less than a monolayer of Ag is present on the surface, XPS showed that up to 60% of the surface Si is bound to Ag, while 20% of the surface Si sites remain covered by a Sn complex. ISS verified that Ag is a surface species and that 80% of the surface is covered by Ag and Sn. Variable angle XPS showed that Ag is raised out of the surface plane, and that it probably also resides over the Si. Analysis of one monolayer Ag f...

Short courses, which are taught intensively by the American Vacuum Society (AVS) for one, two, or five days, represent the most important media for disseminating new educational material on the nature, maintenance, and utilization of the vacuum environment. The development of the AVS course offerings is traced from offering one course to 80 attendees in 1969 to an availability of 38 courses and over 2400 attendees in 1983. The topical content of the courses available is listed, and their relationship to the AVS chapter and divisional structure is reviewed. The means used to develop courses, to select the sites for presentation, and to monitor course quality are discussed. The different management plans used at various stages of growth of the short course program are identified and the economic impact of the AVS program on the Society is discussed. Of all who attend AVS courses, 85 percent of the course registrants are not members of the AVS. The background, professional tasks performed, type of employer, and the challenge of the diversity of student backgrounds for classroom teaching are discussed. The AVS experience can serve as a model for any science-related technical society to develop or expand a continuing education program in its topical area of interest.

For most noble ion-surface systems, the positions of energy-loss spectral peaks from low energy scattering are accurately predicted by the binary collision model. Deviations from the predictions of this model, however, have been observed in a number of systems. While some of these deviations have been established as due to fundamental limitations of the model, others can be explained as instrumental in nature. This paper examines peak shifts due to changes of the beam/target/detector geometry in order that these instrumental difficulties may be separated from those of a more fundamental nature. In particular, a number of mechanisms are shown to modify the nominal scattering angle. When account is taken of these effects, agreement with the binary scattering model is restored. A method is presented by which an improved value of the scattering angle can be determined provided the spectrum contains at least two identifiable peaks. This improved scattering angle can be used to increase the confidence of mass assignments to unknown peaks. Peak shifts resulting from charged insulating samples were reproduced by systematically charging conducting samples. An explanation for both situations is provided in terms of changes in impact energy and scattering angle.

A quartz‐crystal microbalance (QCM) apparatus has been assembled for studying the water sorbed by polymeric materials from 0.1 to 100 μm thick. The apparatus consists of an UHV system with a turbomolecular pump, valves, low‐pressure gauges, a capacitance manometer, a residual gas analyzer, and reservoirs for water vapor and other adsorbate gases. Up to five different polymer coated quartz crystals can be inserted into hangdown tubes using a 20‐in.‐long, water‐cooled, sensor head with appropriate feedthroughs for the electrical connections and thermocouple leads. The QCM controller consists of a power supply, oscillators, frequency meter, and output for obtaining mass change data. The sensitivity of 14 ng/cm2 Hz corresponds to a mass change of about 0.1% for a 100‐nm‐thick polymer film. Sample temperatures are controlled to better than 0.1 °C by immersing the hangdown tubes in a liquid water bath. The controller is interfaced with computers for data acquisition, storage, manipulation, etc. to output data f...

Mass losses of Ablefilms 529, 535, and 550 during curing ranged from 1-1.8 percent of the adhesive. The major gases evolved included the curing agent, solvent, water, carbon dioxide, and carbon monoxide. Exposure of Ablefilm 529 to 2.4 kPa (18 tort) water vapor yielded a saturation uptake of 0.27 percent of the sample mass, which could supply up to about ten times more water than needed for a dew point of 22°C in a volume of 40 mm3. Ablefilm 550 sorbed even greater quantifies of water.

An apparatus consisting of a vacuum ultramicrobalance and optical equipment for measuring transmittance and front surface reflectance of thin films from 400 to 800 nm is described. Thin films formed on substrates by thermal or reactive evaporation can be heated in reactive gases of different compositions and pressures. As the chemical composition of the film changes, the optical changes in the film can be monitored simultaneously using computerized data collection, control, and analysis.

Silvered polymers are being studied as reflectors for concentrators of solar radiation because of their potential for significant cost reduction compared with current glass mirror technology. Thin flexible silvered polymer films form excellent mirrors whose initial performance exceeds the long-range goal of a reflectance greater than 90% with a beam spread of a few mrad. Ongoing real-time weathering tests show that mirror performance has been maintained outdoors for 1 yr; accelerated tests indicate the durability is probably longer than 1 yr. It is demonstrated that stabilizers are needed in an acrylic polymer to maintain the reflectance of the silver and a set of effective stabilizers has been identified. The permanence of the stabilizers may limit mirror durability. Polymeric stabilizers and stabilizers that do not absorb u.v. light are being studied to improve mirror durability and optical performance.

The executive summary is taken verbatim from the published proceedings of a workshop sponsored by the Division of Materials Sciences of the U.S. Department of Energy, in Denver, Colorado, July 1980. The 248-page proceedings documents the consensus of the principal discussions and conclusions. The executive summary refers to details in specific chapters.

Thermal processes can often be characterized by peak reaction temperatures, pre-exponentials, and activation energies, as well as by other parameters. Values of the exponential integralEi(−x), or of a related integralI(x), where the numeric argumentx is a function of activation energy and temperature, are essential to the analyses of many of these processes. It is shown that the use of only the first term of the concomitant asymptotic series to approximate these integrals can result in less reliability than the uncertainty in thermal reaction data. Hence, values ofI(x) which are accurate to 4 significant digits over the range ofx from 15 to 50 are presented.

The transmittance and reflectance of CuO0.67 and CuO films ranging in thickness from 392 to 2335 A have been measured in the wavelength region of 400 to 800 mμ. These data were used to obtain the wavelength dependence of the optical constants of these materials. Differences between the optical properties of CuO0.67 and Cu2O are attributed to differences in stoichiometry rather than to size effects. A method for measuring absolute reflectance is described.

A high sensitivity Faraday susceptibility apparatus employing a quartz beam microbalance is described. With this apparatus, it is possible to measure the susceptibilities of small samples (0.2 mg) and adsorbed gases, to adequately account for ferromagnetic impurities by the Honda‐Owen method, and to carry out measurements over a range of ambient atmospheres and temperatures (80–700°K). An automated null technique was developed for continuous operation in time dependent studies. In practice, the error obtained with this apparatus is 0.1% for precision and ≤1% for accuracy and it is possible to obtain, under favorable conditions, an ultimate sensitivity of ±0.001×10−6 emu/g.

At temperatures below 200 °C, copper films less than 1085 A thick oxidize in 100 Torr of oxygen to form CuO0.67 before nucleation to CuO sets in. The oxidation of copper to CuO0.67 can be described by two parallel absorbing layers. During the oxidation, the transmittance, T, at normal incidence has been measured as a function of the wavelength λ while the mass change of the copper film has been simultaneously recorded with a vacuum ultramicrobalance. The thickness of the two absorbing layers, d1 and d2, has been calculated from the mass data. Using the measured values of T, λ, d1, and d2 and known values for the optical constants, n and k, for annealed copper films, trial values for n and k for the oxide have been inserted into rigorously derived equations for two parallel homogeneous absorbing films on a nonabsorbing substrate. By comparing the values of the transmittance calculated by a computer with the experimental values, k–n pairs are found that yield the measured transmittance. When the k–n pairs a...

Clean [111] oriented silver field emitting tips have been prepared from etched wire by repeated field evaporation and heat treatment. The thermal end-form of the clean surface shows {111}, {100}, and {110} faces if the tip radii are greater than 1000 A. The clean surface does not adsorb residual gases (H2, CO, CH4) under UHV conditions (10−10 Torr region) if its temperature is above 0°C. On heating after field evaporation, the tips exhibit contamination as brigthly emitting agglomerates randomly distributed over the surface. The brightly emitting impurities decrease the work function. The cleaning procedure and the nature of the surface contaminants are discussed. Saubere, [111]-orientierte Feldemissionsspitzen von Silber wurden aus geatzten Drahten durch wiederholte Feldverdampfung und Warmebehandlung prapariert. Die thermische Endform der sauberen Oberflache zeigt {111}-, {100}- und {110}-Flachen, wenn die Spitzenradien groser als 1000 A sind. Die sauberen Oberflachen adsorbieren keine Restgase (H2, CO, CH4) unter UHV-Bedingungen (10−10 Torr-Bereich), wenn die Temperatur oberhalb 0°C liegt. Beim Aufheizen nach der Feldverdampfung zeigen die Spitzen Verunreinigungen in der Form von hell emittierenden Agglomeraten, die statistisch auf der Oberflache verteil sind. Die hell emittierenden Storstellen erniedrigen die Austrittsarbeit. Das Reinigungsverfahren und die Natur der Oberflachenkontamination werden diskutiert.

The optical transmittance, measured from 400 to 800 μm during the complete oxidation of copper films to CuO0.67 at temperatures below 200 °C, has been used to test a model of oxidation by parallel layers. The transmittance at each stage of oxidation was calculated from the thickness of the oxide and metal layers, the optical constants, and the assumption that two homogeneous parallel absorbing layers exist at all stages. By comparing the calculated and experimental values of transmittance, the validity of the “parallel layer” model was established for nearly all stages of oxidation. Deviations in the initial stages are attributed to nucleation. Films oxidized at temperatures exceeding 147°C showed evidence of agglomeration of the metal in the terminal stages of oxidation. The films, deposited at 25°C on Pyrex substrates, are strained. Thus, when they were heated to the oxidizing temperatures of 125°–200°C, they were oxidized and also annealed. The optical constants for strained copper films are compared w...

Clean [111] oriented silver field emitting tips have been exposed to oxygen at 10−3 Torr for 1 min at temperatures ranging from − 170 to 200°C. From 50 to 200°C, an adsorption structure is formed that is stable in oxygen. The structure is characterized by intensely emitting regions on either side of enlarged {110}, {210} and {310} faces and a dark region in the (111)-{100} zone line directions. For adsorption from − 170 to 200°C, the structure of the patterns depends distinctly on the adsorption temperature because the coverages are different and adsorption is activated. Oxygen adsorption at 10−3 Torr for 1 min at 0°C causes an increase in the average work function of 1.15 eV. At 0°C, silver was exposed increasingly at 10−6 Torr until 6100 L was reached. The work function increased progressively by 0.61 eV for this exposure. The {111}, {100}, {311}, {211} and {533} faces are attacked first. Then, the {110} faces are attacked followed by the {210} {310} and {320}. Heating of the adsorption layer formed at 0°C produced no changes in pattern and work function up to 100°C. Between 100 and 200°C, a strong decrease in work function and changes in the pattern result from oxygen penetration into the bulk.

High-purity silver powder (99.97%) subjected to isothermal outgassing, oxygen adsorption, outgassing, and chemical reduction (OAOR cycling) at 320 °C has been shown to contain 750 ppm of unreported volatile impurities and to be reproducible to the chemisorption of oxygen and other gases. To determine some of the volatile contaminants present before cycling and the effect of cycling on their release by the sample, a residual gas analyzer was used to study the gases which were desorbed by heating a sample of silver powder in stages to 900 °C in vacuo. A second sample was subjected to five OAOR cycles at 320 °C and then outgassed in stages up to 900 °C. During the isothermal outgassing of the uncycled sample, the partial pressures of carbon monoxide, carbon dioxide, oxygen, water, argon, and sulfur dioxide increased by as much as ten times between 300 ° and 410 °C and again between 540 ° and 565 °C. The increase in the residual gases results from a combination of bulk diffusion, surface reaction and desorpti...

The purpose of this paper is to report the size of oxide islands or line w idths that can be grown as smaller diameter electron beams are used for the ox idation. The implications of the potential lateral resolution available b etween oxide lines for electronic materials are discussed. The localize d oxide growth on thin Al films occurs in the presence of .5 to 10 keV ele ctron beams and high vacuum level pressures of carbon dioxide or nitrous o xide. Auger electron spectroscopy shows saturation of the O (KLL) signal and depletion of the Al (LMM) signal after an exposure of 5000 l carbon di oxide with a 2 keV beam of 7 A/sq. cm. The oxide is spatially restricted to the beam impact region and is stable for long periods of time in vacuum . The most plausible mechanism for this oxide growth is dissociation of t he carbon dioxide or the nitrous oxide by the electron beam in the region of impingement on or near the surface. Oxygen atoms thus formed can then react with the Al, and carbon monoxide or nitrogen ...

Silvered polymers have been studied for possible mirror applications in concentrators for solar thermal systems. The polymeric mirrors were prepared by vacuum evaporating or dc-sputtering silver onto several candidate polymers for use as second surface mirrors. Specularities were measured at 7 and 15 mrad acceptance angles at 660 nm. The specularity of silvered polymers depends strongly on the topography and bulk properties of the polymer used. It is independent both of the deposition rate from 0.1 to 7 nm/s and from thermal evaporation and dc-sputtering processes. Silvered glass specularities are also independent of deposition rates from 0.1 to 45 nm/s and are typically 93% at 7 mrad. The specularity does not depend on the substrate temperatures during depositions for the range of 5 to about 100°C. In some cases, a metallic film was deposited onto the silver before mounting onto a Corning 7809 glass substrate. Inconel backing of films from 35 to 150 nm thick does not reduce the specularity of sivered polymers at 15 mrad, but does accelerate the degradation of the multilayer combination during accelerated or real-time weathering. After measuring the solar-weighted hemispherical reflectance and the second surface specularity at 660 nm for acceptance angles of 15 and 7 mrad, the silvered polymeric specimens were subjected to accelerated testing in a Weather-Ometer at 60°C, 80% relative humidity, and UV irradiation, or in a QUV at 40°C, UV irradiation and condensation cycles. Real-time testing has also been carried out in the suburban Denver, CO, atmosphere. With exposure, all mirrors prepared show evidence for some or extensive optical and/or visual degradation. The relative durabilities of the various combinations studied are discussed in terms of the silvering method, polymer used, metallic backing for the silver, and adhesive used for mounting the silvered polymer onto a test substrate.

The technique of Fourier transform infrared reflection-absorption (FTIR-RA) spectroscopy has been successfully adapted to studying bulk and interfacially activated photodegradation of several types of polymers on various metallic substrates. The technique enables quali-tative and quantitative study of photochemical reaction mechanisms and rates. A Controlled Environmental Exposure Chamber (CEEC), which permits collection of IR-RA spectra of the polymer/metal samples during their exposure to controlled spectral distributions of UV, temperatures, and gas mixtures, was built into the sample compartment of a Nicolet 7199 FTIR spectrophotometer. Surface analysis, gel permeation chromatography (GPC), UV spectro-scopy, and UV spectroradiometry were used to complement the FTIR-RA results.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The purpose of this paper is to present an extended summary of the oral presentationgiven at the 24th SPIE Symposium. Details of the rationale for the study, methods,procedures, and results are available.' The object of this work was to prepare cuproussulfide films by sulfiding copper in a mixture of hydrogen sulfide and hydrogen, tocharacterize the films, and to establish that solar cell device grade cuprous sulfide couldbe prepared by a method that permits characterization of the pure material before, during,and after reaction in degrading environments. Copper films, deposited in vacuum onto asubstrate suspended from a quartz ultramicrobalance, were sulfided in mixtures of hydrogensulfide and hydrogen until the composition cuprous sulfide was reached. With the gravi-metric apparatus, the optical transmittance (T) and reflectance (R) were also obtained insitu at intervals during the deposition and sulfiding processes. The sulfided films werecharacterized by SEM, ISS, ESCA, SIMS, diffraction, profilometry, resistivity, and Halltechniques after removal from the balance. Between 70 and 94 °C and with hydrogen /hydrogensulfide ratios between 11 and 39:1, copper films can be sulfided to cunrous sulfide in30 -36 hours to produce cuprous sulfide films 100 to 400 nm thick. The SEM data show thefilms are smooth enough to deduce the optical constants from the T and R data. The carriermobility and optical properties were found to be comparable with those reported for devicegrade cuprous sulfide. Composition in depth profiles show only copper and sulfur can bedetected in the films, except for a trace of surface oxygen. The well -characterized cuproussulfide films were found to be stable up to 100 °C when heated in 13.3 kPa of oxygen, andafter a slow reaction up to ca. 225 °C, formed cuprous oxide and cupric sulfate at 300 °C.IntroductionThe technological development of thin film cuprous sulfide /cadmium sulfide heterojunctionsolar cells has resulted in an increased interest in the materials science of cuprous

A technique is presented for in situ study of degradative changes in polymeric coatings on metallic substrates. The technique uses a controlled environment chamber in conjunction with a Fourier-transform infrared (FT-IR) spectrophotometer. The chamber design permits collection of IR reflection-absorbance spectra from a sample undergoing exposure to controlled ultraviolet (uv) radiation, gas mixtures, and temperatures. Initial data presented confirm the ability of the technique to provide information regarding the bulk photochemistry of bisphenol-A polycarbonate coatings on gold and aluminum substrates. Refinements of this technique should allow a detailed kinetic study of degradative reactions at the polymer/metal interface.

This report describes the experimental work and results from the second phase of the Matrix Approach to Testing Mirrors (MATM). Mirror specimens are subjected to heat, water vapor, pollutants, ultraviolet light, and mechanical stress for up to eight weeks. Analysis concluded that the degradation rates are very sensitive to temperature; above 95/sup 0/ to 100/sup 0/C, agglomeration causes the silver film to degrade rapidly; degradation is more severe in high humidity pollutants did not substantially alter the degradation rates; ultraviolet light did not significantly alter the degradation of solar reflectance; no synergistic effects were observed; specular and hemispherical reflectance techniques detect and quatify the early stages of degradation; and darkfield microphotography is a good technique for studying mirror degradation.