Glass formation and structural studies of glasses in the TeO2 – ZnO – Bi2O3 – Nb2O5 system.

Abstract In this study we determined the glass formation region in the TeO 2 - ZnO - Bi 2 O 3 - Nb 2 O 5 system. The investigation covers TeO 2 - based glasses containing ZnO (from 10 to 40 mol%), Bi 2 O 3 (6–10 mol%) and Nb 2 O 5 (6–10 mol%). The glasses obtained were transparent and yellow in colour. The thermal stability of the samples determined by DTA was found to be about 100 °C. Some physical characteristics (density, molar volume, oxygen molar volume and oxygen packing density) were estimated as well. The analysis of IR spectra showed that the network of glasses consists mainly of TeO 4 (tbp) units, while Raman spectroscopy revealed the existence of TeO 4 (tbp), TeO 3+1 and TeO 3 (tp) units. The UV–Vis spectroscopy established a red shifting of the cut-off depending on composition and the glass rich in TeO 2 exhibited cut-off at about 388 nm while that with low TeO 2 content was 378 nm. Highlights • Glass formation region in the TeO 2 – ZnO – Bi 2 O 3 – Nb 2 O 5 system was determined. • Structural, thermal and optical characterization of the multicomponent tellurite glasses was performed. • The short range order of glasses is determined by TeO 4 , TeO 3+1 , TeO 3 , NbO 6 , BiO 6 and ZnO n (n = 4, 6) structural units. • ZnO demonstrates dual role during the amorphous network formation while N 2 O 5 and Bi 2 O 3 oxides act as modifiers. [ABSTRACT FROM AUTHOR]