New quarternary glasses in the systems TeO2-BaO-SrO-Nb2O5 and TeO2-BaO-SrO-Ta2O5 are prepared, and are found to have improved thermal stabilities and refractive indices, making them suitable for photonics device applications. Systematic Raman spectroscopic studies of these glasses are undertaken to unravel the presence of various structural units, and the contributions made by them with varying modifier oxides contents have been quantified. A comparative study is made on the evolution of various structural units with the addition of modifier oxides in the two glass systems. The Raman bandwidths of these glasses are broader compared to conventional tellurite glasses. Both glass systems show an additional Raman band beyond 870cm-1 that is not present in other tellurite glass systems.
