Thermal characterization of novel magnesium oxyhalide bismo-borate glass doped with VO2+ ions

In the present report, physical and thermal characterizations of magnesium oxyhalide bismuth borate glasses in the composition range of (x = 0, 2, 5, 7 and 10) containing 2 mol% of V2O5 prepared by standard melt-quench technique have been discussed. The non-crystalline nature of prepared glasses has been identified through peak free X-ray diffraction profiles. Density (D), molar volume (V (m)) and oxygen packing density have been measured/calculated, and varying trends are discussed by relating with physical changes governed in prepared glass structures on increasing/changing the halogen (fluoride/bromide) ions. The differential thermal analysis (DTA) and thermogravimetry have been carried out in the temperature range of 200-900 A degrees C. Glass transition temperature (T (g)) and melting temperature (T (m)) are determined from the DTA thermographs. The glass stability parameter, T (g)/T (m) is calculated from the obtained values of characteristic temperatures and a sudden decrease in stability at x = 5.0 is observed in both series which reflects that halide ions (F-/Br-) modify the glass structure at low concentrations (up to 5.0 mol%) and contribute to glass network formation at high concentrations (> 5.0 mol%). Infrared absorption spectra have been recorded in the mid-IR range and evaluated to report the possible cause of band vibrations present in the spectra.