Measurements were made of the electrical conductivity and differential thermal analysis on alloyed samples of Ge and Sn with Se, prepared under vacuum, to evaluate their glass-forming tendencies. It was possible to esrimare the characteristic temperatures fig, T, and T,I and the crystallization kinetic parameters of the glasses (crystallization mode, n, rare of crystallization, K, and activation energy, E,). The previously obtained parameters have been evaluated according to Johnson-Mehl Avrami (J. M.A.) model. The cohesive energy and related parameters such as effective average coordination number < reff > , the number of constraints per atom, N,,,, were also calculated. Experimental results exhibit a nonmonotonic behaviour with < reti>. This nonmonotonic behaviour, revealed the presence of concentration-dependent intrinsic homopolar-bond defects when the number of mechanical constraints, N,,,, exceeds the number of degrees of freedom, N,. It was found that there is a correlation between the chalcogenide glass forming ability and the number of lonepair electrons for a chalcogenide system. An attempt has been made to evaluate this correlation according to a simple criterion for computing rhe ability of a chalcogenide system to retain its vitreous stare proposed by
Liang. Our experimental results support to some extent the above criterion in the case of Ge-Sn-Se ternary alloy.