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Silver-containing glasses are promising candidates for photonic applications, due to the potentiality of spectroscopic properties of silver nanoclusters (NC's) and/or silver metallic nanoparticles. In this framework, silver-containing fluorophosphate glasses are candidates with a strong potential. Indeed, combined with femtosecond laser irradiation, silver NC's may be tailored in three-dimensional fluorescent micro-structures, whose spectroscopic properties have been investigated, revealing the creation of silver NC's but also of NP's during laser irradiation in the studied fluorophosphate glass. Additionally, the photo-inscription of silver NC's is correlatively accompanied by a positive index change, which has led to the demonstration of optical waveguiding behavior. Finally, the management of the reservoir of available silvers for laser inscription is investigated. Unlike previous observations made in standard oxide phosphate glasses, the considered silver-containing fluorophosphate glass exhibes an intriguing ability to be re-written when subjected to successive overlapping laser irradiations. Upon the optimization of compositions with tailored photo-sensitivity, the re-writable ability of fluorophosphate glasses paves the way to the design of advanced photonic devices such as photonic optical circuits, evanescent sensors or 3D high-density optical data storage. [ABSTRACT FROM AUTHOR]

New glass compositions were investigated in this specific proportion (90-x)TeO 2 -10GeO 2 -xPbF 2 in order to study the influence of lead fluoride content on the thermal, structural and optical properties. Glass samples with x = 5 to 30% were prepared by melt-quenching method. Thermal characterizations by DSC allowed to identify a clear decrease of the glass transition temperature as well as a very distinct crystallization behavior for higher PbF 2 contents. Raman spectroscopy suggests a progressive PbF 2 incorporation with conversion of TeO 4 to TeO 3 units related with the modifier behavior of PbF 2 in the glass network. X-ray diffraction patterns of crystallized samples support these results since crystalline TeO 2 was detected for lower PbF 2 contents whereas lead tellurite Pb 2 Te 3 O 7 was identified for the most lead fluoride concentrated sample. UV–Vis–NIR absorption spectra are in agreement with a progressive increase of the optical bandgap with lead fluoride concentration. Emission spectra of Eu 3 + doped samples also pointed out a progressive structural change around Eu 3 + ions with more symmetric sites. Finally, experimental lifetimes, Judd-Ofelt parameters and quantum efficiencies were obtained from these samples and exhibited a strong dependency of the lead fluoride contents, suggesting that these new fluorotellurite glasses are interesting hosts for rare earth ions. [ABSTRACT FROM AUTHOR]

Tungsten phosphate glasses are known to be promising materials for several applications in optics such as non linear optical properties, lower phonon energy or photochromic effects related with tungsten oxide incorporation inside the phosphate network. In this study, lead fluoride has been incorporated in a 60NaPO 3 –40WO 3 glass composition according to the ternary molar compositions (100 − x )[0.6NaPO 3 –0.4WO 3 ]– x PbF 2 with x varying from 0 to 60 mol%. The structural changes as a function of composition were investigated by thermal analysis, UV–visible absorption, Raman spectroscopy, X-ray diffraction of the crystallized samples, and Eu 3+ emission in the visible. While DSC analyzes points out a strong decrease in the glass network connectivity and higher crystallization tendency with increasing PbF 2 contents, Raman spectra clearly identify a progressive incorporation of PbF 2 in the phosphate network with the formation of terminal P F and W F bonds. These results are also in agreement with the crystallization of β-PbF 2 observed for the most lead fluoride concentrated samples. Investigation of Eu 3+ emission data in the visible showed longer 5 D 0 excited state lifetime values and higher quantum efficiencies. These results are discussed in terms of the assumption of higher local symmetry around Eu 3+ with increasing PbF 2 contents. [ABSTRACT FROM AUTHOR]

Abstract: Crystalline lead–pyrophosphate precursor was prepared in aqueous solution from lead nitrate and phosphoric acid and characterized by X-ray diffraction, thermogravimetry and Raman scattering. This crystalline lead–phosphate was then used to prepare glass samples in the binary system Pb2P2O7–WO3. Dependence of WO3 content on thermal, structural and optical properties were investigated by thermal analysis (DSC), Raman spectroscopy, UV–visible and near-infrared absorption and M-Line technique to access refractive index values. Incorporation of WO3 in the lead–pyrophosphate matrix enhances the glass transition temperature and thermal stability against devitrification, favors formation of Ph name="sbnd" />W bonds and WO6 clusters. In addition, optical properties are strongly modified with a redshift of the optical bandgap with WO3 incorporation as well as an increase of the refractive index from 1.89 to 2.05 in the visible. [Copyright &y& Elsevier]

Abstract: Glasses were prepared in the pseudo-binary system (1−x)AgPO3–xWO3 (0≤×≤0.6mol%). The structural evolution of the vitreous network was studied as a function of composition by thermal analysis, Fourier Transform Infrared spectroscopy (FTIR), Raman scattering, high resolution 31P solid state NMR and XANES at the W-L1 absorption edge. For compositions with x ranging from 0 to 0.5 a pronounced increase in the glass transition temperature is observed, suggesting a significant increase in the glass network connectivity. At the same time Raman spectra indicate that tungsten atoms are linked to non-bridging oxygen atoms (W–O- or W=O bonded species) whereas the 31P MAS-NMR spectra indicate the successive formation of new P–O–W linkages. The formation of some anionic tungsten sites (if these are revealed by the presence of W–O terminal bonds) implies an increase in the average degree of polymerization of the phosphate network, which is consistent with the compositional evolution of the 31P MAS-NMR spectra at low x values. For higher x-values, the Raman spectra indicate the presence of W–O–W linkages. W-L1 XANES data indicate that at least 90% of tungsten atoms are octahedrally coordinated. [Copyright &y& Elsevier]

Abstract: A simulation of erbium-doped glass systems, which provides population density for the excited states involved in the 1.5μm and also for 2.7μm emissions when pumped around 980nm, is presented. To describe the diode pump laser processes, a theoretical model based in a coupled system of differential rate equations was developed. The approach used and the obtained spectroscopic parameters are discussed. The materials under study are two oxide glasses, lead fluoroborate (PbO–PbF2–B2O3), and heavy metal oxide (Bi2O3–PbO–Ga2O3) and a fluoride glass (ZrF4–BaF2–LaF3–AlF3–NaF), all of them doped with Er3+. [Copyright &y& Elsevier]

Abstract: Vitreous samples were prepared in the NaPO3–BaF2–WO3 ternary system with high WO3 concentrations. These glasses exhibit a strong absorption in the visible due to the presence of reduced tungsten species and the use of oxidizing species is required. The couple Sb2O3/NaNO3 was introduced in the composition and allowed to obtain transparent glasses. These oxidized samples were illuminated by visible laser radiation and showed an efficient volumetric photochromic effect. The photosensitive effect appeared as a dark spot throughout the entire volume of the glasses. The effect was investigated by several techniques such as, UV-visible absorption, Raman and XANES at the L1 and L3 tungsten absorption edges. The results suggest a photoreduction of tungsten atoms without structural changes of the viteous network. Finally, the photochromic effect can be erased by thermal treatment at 200 °C for a few minutes. [Copyright &y& Elsevier]

Abstract: In this work, a new organic–inorganic hybrid material has been synthesized by the incorporation of croconate ion into a calcium polyphosphate coacervate. The hybrid so obtained was characterized by means of electronic and vibrational spectroscopies. The material is a homogeneous mixture described by a structural model, which includes helical chains of polyphosphate ions, where the calcium ion occupies the internal vacancies of the structure. The croconate ion appears to be occupying the regions outside the polymeric structure, surrounded by several water molecules. The electronic spectrum of the incorporated material shows a broad band peaking at the same wavelength region (363nm) observed for the aqueous solution of croconate ion, and manifesting the Jahn-Teller effect as evidenced by the doublet structure of the band. The infrared spectrum is widely dominated by the absorption bands of the polyphosphate ion and the appearance of the carbonyl stretching band at ca. 1550cm−1 indicates the presence of croconate ion incorporated in the structure. The Raman spectrum of the material shows several vibrational bands related to the oxocarbon moiety; most of them are shifted in comparison with the free ion. These shifts can be understood in terms of strong hydrogen bonding interactions between water molecules and the oxocarbon moiety. The low temperature methodology proposed here can be well used in the preparation of new phosphate glasses containing organic moieties opening the route to an entirely new class of hybrid glasses. [Copyright &y& Elsevier]