Dual role of ZnO and its impact on thermal and structural properties of tellurium-vanadate glass system

Abstract

In the present study, we have reported the synthesis and characteristic properties of xZnO-(60−x)TeO₂-40V₂O₅ (x = 20, 25, 30, 35, and 40 mol%) glass systems. The conventional melt-quenching method is adopted for the synthesis. The effect of ZnO concentration on the glass network has been studied using Raman and IR studies. The glass transition temperature ($T_g$) was found to increase with ZnO content. Structural analysis showed the presence of TeO_4, TeO₃₊₁ and TeO₃ groups along with VO₄ and VO₅ coordinated vanadium groups. XPS analysis of oxygen (O 1s core level) spectra showed an initial increase in non-bridging oxygen by ∼ 62.27 %. However, it starts decreasing by ∼ 53.77 % with a further increase in ZnO content. The changes observed in the system are attributed to ZnO acting as a network modifier at lower concentrations however, as the ZnO content keeps increasing, it starts acting as a network former.