Spectroscopic and thermal investigations on Zn2+ and Ba2+ ions modified 30TeO2-39.5B2O3-(30-x)ZnO-xBaO-0.5V2O5 (0 ≤ x ≤ 30 mol %) glass system

Abstract

Melt quenching technique was employed to prepare glasses with compositional formula 30TeO2-39.5B2O3-(30-x)ZnO-xBaO-0.5V2O5 (0 ≤ x ≤ 30 mol%). Various characterization tools viz., X-ray diffraction (XRD), Energy dispersive X-ray (EDX) includes color mapping images, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), Raman, Differential scanning calorimetry (DSC), UV–Vis absorption and Electron paramagnetic resonance (EPR) were used in this investigation for the characterization of these glasses. The XRD patterns together with DSC thermograms asserted the amorphous nature of all glasses. FTIR and Raman vibrational analyses has unveiled the formation of B-O--Ba2+-O− and Te-O−--Ba2+-O− wherein the bonds with Ba2+ ions are mostly ionic. DSC investigations disclosed that the increase of BaO at the cost of ZnO declined the crystal phases and favored the amorphosity and this behavior causes these glasses more advantageous for fiber drawing. The Urbach energy (ΔE) lies in between 0.28 and 0.57 eV and suggested the glasses containing high ZnO has less defects. EPR data validated that Ba2+ ions might surround V4+ ions as Ba2+-O-V4+=O by replacing Zn2+-O-V4+=O linkages. The other optical properties were discussed in detail by correlating the structural variations noticed from both FTIR and Raman data analyses.