Thermal properties of TeO2-ZnO-Na2O glasses: effect of Dy2O3 doping

Abstract

Over the years there has been numerous researches on thermal stability and other thermal parameters of glasses. Among the glasses, tellurite glasses has become more interesting but challenging lately. These properties are essential in unravelling the physical properties of the glasses. But there is not much information on thermal properties of Dysprosium doped zinc sodium tellurite glass, hence the need for this study. Therefore systematic series of quaternary zinc sodium tellurite glasses doped with dysprosium ion in the form (65-x)TeO₂-25ZnO-10NaO-xDy₂O₃ (where x = 0.0, 0.4, 0.8, 1.2, 1.6, and 2.5 mol%) have been successfully prepared via conventional melt quenching technique. X-Ray Diffraction (XRD) pattern was used to confirm the amorphous nature of the glasses, while density (ρ) of the prepared glasses were obtained via Archimedes method. Differential thermal analysis (DTA) curves for the studied glass samples with different Dy₂O₃ contents have been obtained to determine the glass transition temperature (?_g), crystallization temperature (T_c), glass stability temperature (ΔT_s) Hruby’s parameter (H). From the DTA profile, the glass transition temperature T_g, was in the range of 287-302 °C, crystallization temperature T_c from 408-502 °C, glass melting temperature Tm, 662-659 °C and crystallization onset temperature T_x is estimated to be between 354-389 °C. The thermal stability factor, defined as ΔT_s = T_c - T_g, for all the samples are higher than 100 °C while Hruby’s parameter H, is 0.47-1.33. These suggest that the prepared tellurite glass exhibits a good thermal stability and consequently might be a potential candidate for fibre drawing and other nonlinear optical devices.

Keywords: Tellurite glass, DTA, Thermal stability & Hruby’s Parameter