Non-isothermal crystallization kinetics, optical and structural properties of MgO-doped vanadate glasses

This paper deals with the crystallization kinetics, optical and structural features of V_2−xMg_xO_5−δ (x = 0.15–0.30) glasses under non-isothermal conditions using Lasocka, Kissinger and Augis-Bennett approaches. Raman spectra confirm the layer structure of vanadium in the present glasses. The optical band gap decreases from 2.64 to 2.20 eV with an increase in MgO doping, while refractive index (n) increases from 2.50 to 2.65 with an increase in MgO doping. The activation energy of glass transition and crystallization increase from 150 to 229 kJ mol⁻¹ and 256–442 kJ mol⁻¹, respectively, with the doping of MgO in V₂O₅. The kinetic parameters calculated from different approaches are found to be in a good agreement with each other. The fragility index increases from 29 to 51 with increasing MgO content in place of V₂O₅. The values of \({f}_{\text{g}}\) $f_{\text{g}}$ and \({E}_{\text{c}}\) $E_{\text{c}}$ are found to enhance with changes in heating rates due to the strong influence of heating rates on glass transition temperature.