Raman Spectra and Constitution of Binary Tellurite Glasses Containing Typical Network Modifying Cations.

The 720 and 780cm-1 components of the deconvoluted Raman spectra of glasses in the systems RnO-TeO2 (R=Li, Na, K, Ba, Zn) were attributed to TeO3 groups and the 665cm-1 band was to TeO4 groups. The theoretical values of the molar ratio TeO3/TeO4 derived from an assumed vitrification reaction were compared with the ratio derived from the intensity ratios of the Raman bands, I(720)/I(665) and I(780)/I(665). It was indicated that [O2/2Te=O] and [O1/2Te(=O)-O]- units were induced by the addition of network modifying oxides in the composition range of lower atomic ratio O/Te. It was proposed that the decrease in the rate of increase of the ratio TeO3/TeO4 in the range of larger O/Te was due to the equilibrium TeO4/2↔[O2/2Te=O] favoring the former unit.