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 E-t, 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 T-g on the heating rate fl, the Et has been calculated on the basis of Moynihan and Kissinger models. Results indicate that T-g and (E)t attain their minimum values at 6 at% of Sn. Thermal stability has been monitored through the calculation of the temperature difference T-c-T-g, the stability parameter S, the enthalpy released during the crystallization process H-c and the crystallization rate factor K-p. The GFA has been investigated on the basis of Hurby parameter H-r, which is a strong indicator of GFA, and the relaxation time. Results of GFA are in good agreement with the fragility index F-j 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 >approximate to 2.36, which is thermally most stable. (C) 2007 Elsevier B.V. All rights reserved.