Thermal, FTIR and EPR studies of transition metal ions doped with tellurite magnesium borate glass at room temperature
R Palani, V Gobala Vijayan
Glasses with composition 15TeO2-10MgO-(75-x) B2O3 -xNiO and 15TeO2-10MgO-(75-x) B2O3 - xWO3 (where x = 0 to 1.0 in steps of 0.2 mol %) have been prepared with a conventional melt–quenching method. The glass samples were characterized by using X-ray diffraction (XRD), Thermo Gravimetric - Differential Thermal Analysis (TG - DTA), Fourier Transform Infrared Spectroscopy (FTIR), and Electron Paramagnetic Resonance (EPR). XRD scans evidenced the amorphous state of as-quenched samples. To recognize the thermal behavior of the glasses, glass transition (Tg), crystallization peak (Tp), melting temperature (Tm) and the glass stability against crystallization (∆T) were calculated from the thermal analyses. FTIR spectrometry in the spectral range 400 – 4000 cm-1 at room temperature was interpreted in terms of the structural transformations on the glass network, according to the changing B2O3, NiO and WO3 content. The EPR spectra have been traced in X-band (ʋ ≈ 9.78GHz) at room temperature. The resonance signals at g ≈ 2.0 - 2.3 were found for the metal ions Ni2+ and W6+ respectively. Electron paramagnetic resonance data suggest the bonding between transition metal ions and ligands as an ionic in nature.