RAMAN-SPECTRA AND THERMAL-ANALYSIS OF A NEW LEAD-TELLURIUM-GERMANATE GLASS SYSTEM

Differential scanning calorimetry (DSC) and Raman scattering studies o f a new glass system, lead-tellurium-germanate glasses in the form of (90 - x)GeO2 . xTeO(2) . 27PbO . 10CaO with x = 0, 10, 20, 30, 40, are reported. The glass samples were fabricated using a conventional melt -quenching method. The Raman spectra and possible glass structures are discussed for different TeO2 contents. The results indicate that incr easing TeO2 content up to 30 mol% in the glass system decreases the gl ass transition temperature and melting temperature, and suppresses the crystallization tendency in the fiber pulling temperature range. The lead-tellurium-germanate glass, GTPC, possesses a larger refractive in dex and a smaller maximum phonon energy than that of a lead-germanate glass, 63GeO(2) . 27PbO . 10CaO, and shows a better thermal stability compared to a tellurite glass, 75TeO(2) . 20ZnO . 5Na(2)O (TZN). These improved properties could be beneficial for fabricating rare-earth do ped fiber devices.