Glass transition activation energy, glass-forming ability and thermal stability of Se90In10−xSnx (x=2, 4, 6 and 8) chalcogenide glasses

Differential scanning calorimeter (DSC) has been employed to investigate the glass transition activation energy Et, thermal stability and the glass-forming ability (GFA) of Se90In10−xSnx (x=2, 4, 6 and 8) chalcogenide glasses. From the dependence of the glass transition temperature Tg on the heating rate β, the Et has been calculated on the basis of Moynihan and Kissinger models. Results indicate that Tg and Et attain their minimum values at 6 at% of Sn. Thermal stability has been monitored through the calculation of the temperature difference Tc–Tg, the stability parameter S, the enthalpy released during the crystallization process Hc and the crystallization rate factor Kp. The GFA has been investigated on the basis of Hurby parameter Hr, which is a strong indicator of GFA, and the relaxation time. Results of GFA are in good agreement with the fragility index Fi calculation and indicate that Se90In4Sn6 is the best glass former. The compositional dependence of the above-mentioned parameters was discussed on basis of the topological model of Thorpe and Phillips and the critical composition found to occur at an average coordination number 〈z〉≈2.36, which is thermally most stable.