Crystallization, kinetics and mean bond energy of glasses from the GeSe₂-GeTe-SnTe system

Chalcogenide glasses from the GeSe₂-GeTe-SnTe system were synthesized by direct synthesis with following quenching in ice cold water. The crystallization temperatures of the as-prepared samples were determined using differential thermal analysis at heating rates of 10, 15, 25 and 36 K/min. Al₂O₃ and Se were used as reference sub-stances. The standard substances and the investigated sample in quantity of ≈ 0.3 g were placed in crucibles, which are sealed at residual pressure of ~ 1.10^-3 Pa. The activation energy of crystallization, as main kinetic parameter characterizing this process, was calculated by the Kissinger and the Augis&Bennett models. The values, obtained by the two independent models, coincide. The basic thermodynamic parameters of the crystallization process (enthalpy and entropy alternation) were defined. The enthalpy alternation of the selenium crystallization was calculated, as its crystallization heat is known.The overall mean bond energy ‹E›, the mean coordination number ‹Z›, the mean bond energy of the average cross-linking/atom and the average bond energy per atom of the "remaining matrix" - Ēc and Ērm, as well as the average heteropolar bond energy Ehband the degree of ,,cross-linking/atom" Pp are calculated.A correlation between the investigated parameters and the glasses' composition was established.Keywords: chalcogenides, glass transition, crystallization, kinetics, thermodynamics, mean bond energy.