Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10155535 | Journal of Non-Crystalline Solids | 2018 | 8 Pages |
Abstract
This work presents the production and characterization of a new prolific binary glass system based on SbPO4-GeO2. The dependence of GeO2 content on thermal, structural and optical properties were investigated by means of thermal analysis, Raman, UV-Vis-NIR, infrared, M-lines and EPR spectroscopy. Glass transition temperatures remain constant around 410â¯Â°C when GeO2 content is increased, indicating that GeO4 units are not responsible for increasing the connectivity of PO4 units. Thermal stability linearly increases as a function of GeO2 content, reaching a value around 400â¯Â°C for glass containing 90â¯mol% of GeO2. Raman spectroscopy was used to evaluate the glass structural changes when GeO2 is incorporated from 30 to 90â¯mol% indicating a gradual change from a phosphate to a germanate glass skeleton. The optical window extends from 350â¯nm at UV region, up to 2.7â¯Î¼m in the middle-infrared region limited by the multiphonon cut-off due to the strong OH absorption. M-lines technique shows that increasing GeO2 content decreases the refractive index, mainly because the lower concentration of higher polarizable antimony atoms. EPR spectra of heat treated V2O5 doped glasses, at different temperatures above the glass transition temperature, shows the characteristic eight-line hyperfine splitting spectrum. The spin Hamiltonian parameters obtained from the simulated spectra indicates that the paramagnetic tetravalent vanadium ions in the glasses exist as vanadyl form VO2+, located in axially distorted octahedral sites. For glasses treated at higher temperatures a second VO2+ component appears in the EPR spectra and the analysis of the spin-Hamiltonian parameters suggests that these vanadyl ions are in more tetragonal distorted octahedral sites than those in the glass.
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
Murilo Montesso, Danilo Manzani, José P. Donoso, Claudio J. Magon, Igor D.A. Silva, Mario Chiesa, Elena Morra, Marcelo Nalin,