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Silver particles generated by the evaporation-condensation method were deposited to form a film on a silica glass substrate. The films thus obtained consist of nano-sized silver particles. Nonlinear refractive index, γ and nonlinear absorption coefficient, β determined by using Z-scan technique were both negative, while γ in the literatures for the silver particles-dispersed-glass composites was positive. The absolute value of y for the as-deposited samples was increased as absorption peak wavelength due to surface plasmon resonance became close to the laser wavelength used in the measurement. The particle size (D) dependence, especially D^ dependence of y was clearly observed for the films which were prepared at different particle generation temperatures and annealed at 170℃, and consisted of particles of 26 to 46 nm in size. This dependence was explained in terms of the quantum confinement effect.

Alumina gels were prepared from aluminum-sec-butoxide by sol-gel method at 0℃ using HNO_3 as a catalyst. The crystallization behavior of the gel was compared with that of HCl-catalyzed alumina gels. α-Al_2 O_3 did not form until 950℃ in HNO_3-catalyzed gels, while HCl-catalyzed one partially transformed to α-Al_2O_3 around 500℃. Corundum-seeding affected crystallization in a different way as compared to the HCl-catalyzed one, i.e., the α-transformation in the temperature range of 800 to 1000℃ was better enhanced by seeding and was completed at 800℃ when seeded to a level of 5 mass%. It was considered that NO_3 ions assisted the building of a gel structure in which aluminum or oxide ions are readily diffused at temperatures higher than ～800℃.

The structure change of perhydropolysilazane (PHPS) films during pyrolysis to form silica glass films was examined using FT-IR, DTA/TG and X-ray radial distribution analyses. It was found that above 200℃, the films behaved like tri-ethoxy-silane,HSi(OC₂H₅)₃ -derived silica gel, and became almost free from other chemical species than SiO₂ at 400 to 500℃. The skeleton structure of the PHPS-derived films was considered to be constructed with 4 fold siloxane ring (cyclic siloxane tetramer) units, and its thermal change was interpreted as the transformation of the 4-fold siloxane ring units to the 6-fold siloxane ring units like in the alkoxy-derived silica gels.

Deposition behavior of MgO-added Al2O3 coating layers on Pt wires by the electrophoretic deposition and sintering of those coating layers were examined. Electrical conductivity of the bath solution and amount of deposited Al2O3 were increased by adding MgO into the bath. Mg(acac)2 (magnesium-acetylacetonate) formed through the reaction of MgO with acetylacetone, which was thermally decomposed to MgO by calcination above 400°C. Crystalline phases in the coating layers sintered at 1500°C changed from α-Al2O3 + MgO to α-Al2O3 + spinel (MgAl2O4) or spinel + MgO, with increasing the MgO content. It was found that layer shrinking and crack formation depended on the amount of MgO added to the bath. Crack-free sintered thick layers were obtained when more than 10 mass% MgO was incorporated. Thermal decomposition of Mg(acac) 2 to MgO, leaving pores in the layer was considered to be the crucial processes to avoid crack-formation in the sintered coatings.

The effect of powder characteristics (such as specific surface area and morphology) and iodine addition on the electrophoretic deposition (EPD) coating of alumina on Pt wire was investigated. Electrical conductivity of the bath solution was increased by adding iodine and depended upon specific surface area of alumina powder. Moreover, adding a suitable amount of iodine led to a remarkable improvement of stability of the bath solution, and uniform EPD layers resulted. Round shaped alumina produced by chemical vapor deposition (CVD) method was more suitable than irregular shaped alumina made by sol-gel method for preparing thick and uniform layers. The difference of deposition behavior was explained in terms of electrical resistance of the formed alumina layer and the bubbling of H2 gas generated during deposition. Crack-free alumina 〜50 μm thick layers could be formed on Pt wire by sintering at 1500°C.

Third-order optical nonlinearity of glass-based materials was measured by third-harmonic generation and degenerated four wave mixing method. In nonresonant-type nonlinear galsses, third-order nonlinearity is basically depending on the refractive index. On the other hand, in resonant-type glasses the magnitude of χ⁽³⁾ is as large as 10⁻⁸ esu, which is comparable the bulk semiconductor without slow decay time.