THERMAL-STABILITY OF THE AMORPHOUS SYSTEM AS-SE-I

The effect of adding iodine to the binary systems As-Se on the thermal stability of the ternary glasses thus formed was investigated by DTA and DDTA. The investigated glasses corresponded to different regions of the phase diagram, i.e. they had different contents of As and I and, consequently, contained different types of structural units. In the investigated ternary systems with iodine, the crystallization effect appears at a lower temperature than in the binary glass As40Se60, and the same holds for the temperatures of softening and melting. For both binary and ternary systems, the activation energies of crystallization were determined. The glass As40Se60 exhibited a somewhat higher activation energy, i.e. a somewhat lower tendency to crystallize than the ternary system. The critical cooling rates of the melts for minimum degree of crystallinity were estimated. The obtained values are approximately equal for the binary (As2Se3) and ternary (AsSeI) systems.