Physical, Optical, Structural and Thermal Studies of xWO3 + (30 − x)As2O3 + 70TeO2 (where x = 10, 20, 30 mol%) glasses by UV–vis, Raman, IR and DSC Studies

Abstract

Optical, Structural and Thermal properties of xWO3 + (30 − x)As2O3 + 70TeO2 glass system (where x = 10, 20, & 30 mol%) have been investigated by Optical absorption, Raman & FT-IR, and DSC studies respectively. Physical properties such as, density (ρ), molar volume (Vm), oxygen packing density (OPD), and oxygen molar volume (Vo) are determined for all the glass samples. Density and oxygen packing density (OPD) of glasses have been increasing monotonically with increase in WO3 content in the range 6.52–6.99 g m/cc, and 85.951–88.690 mol/l respectively. These values are correlated with molar volume and oxygen molar volume that are decreasing linearly with increase in WO3 content (10–30 mol%) falling in the range 26.745–25.932 cm3/mol and 11.628–11.274 cm3/mol respectively. The optical transitions and electronic band structure has also been investigated through optical absorption spectra. The fundamental absorption edge is measured in the short wavelength of the visible region, that shows, glasses exhibits the redshift (449 → 483 nm), at photon energy in the range 2.89–2.70 eV for direct allowed transitions. Raman and IR spectral studies reveals that the glass network consists of TeO4 (tbp), TeO3/TeO3+1 (tp), WO6 (octahedral), WO4 (tetrahedra) and AsO3 groups as basic structural units. Thermal behavior of the glasses was studied in terms of glass transition temperature (Tg), onset crystallization (To), peak crystallization (Tp) temperatures, and the thermal stability (ΔT) from DSC thermogrms. In the present glass system, it is found that the glass transition temperature (Tg = 331 → 341 → 353 °C) and thermal stability (ΔT = 56 → 93 → 120 °C) both increases linearly with increase in concentration of WO3 (10, 20, & 30 mol%).