Raman spectra and thermal analysis of a new lead–tellurium–germanate glass system

Abstract

Differential scanning calorimetry (DSC) and Raman scattering studies of a new glass system, lead–tellurium–germanate glasses in the form of (90− x)GeO 2· xTeO 2·27PbO·10CaO with x=0, 10, 20, 30, and 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 TeO 2 contents. The results indicate that increasing TeO 2 content up to 40 mol% in the glass system decreases the glass 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 index 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 2O (TZN). These improved properties could be beneficial for fabricating rare-earth doped fiber devices.