Structural impact of tungsten ions on ZnO–Sb2O3–As2O3 glass system

Five glasses in the quaternary system 5 ZnO–(50 − x) As2O3–45 Sb2O3: x WO3 with the values of x ranging from 0 to 20 mol% (in steps of 5 mol%) are prepared. The samples are characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and differential thermal analysis (DTA) techniques. The DTA studies have indicated that the glass forming ability decreases with the increasing content of WO3. A number of studies, like, spectroscopic (optical absorption, IR, Raman, ESR spectra) and dielectric studies (dielectric constant ɛ, loss tan δ, a.c. conductivity σa.c.) over a wide range of frequency and temperature and dielectric break down strength at room temperature, have been carried out and are analysed in the light of different oxidation states and environment of tungsten ions in these glasses. These glasses have potential photonic applications.

► The thermograms show decreasing trend in Tg from 413 to 316 °C.
► The optical band gap (Eo) is found to decrease gradually from 2.68 eV to 2.51 eV.
► IR spectra explore progressive modifying action of tungsten ions.
► ESR spectra manifest that the glass matrix gradually looses the covalent character.
► Dielectric parameters emphasize that tungsten ions occupy octahedral positions and causes devitrification.