GIBBS-DIMARZIO EQUATION TO DESCRIBE THE GLASS-TRANSITION TEMPERATURE TRENDS IN MULTICOMPONENT CHALCOGENIDE GLASSES

High purity chalcogenide glasses incorporating Ge, Sb, Se, As and Te were prepared by vacuum melting of previously distilled 5 N to 6 N pure raw materials from which the surface oxide was also removed in some instances. Glass transition temperatures, T(g), of several chalcogenide glasses prepared by similar processing techniques were determined using differential scanning calorimetry (DSC). An empirical relationship between the glass transition temperature and average coordination number is proposed by modifying the Gibbs-DiMarzio equation for glass transition of a cross-linked polymer as a function of cross-link density. The results for the T(g) of three 'iso-structural' systems are reported and discussed in light of presumed structural arrangements in these glasses.