Isoconversional Analysis of Thermally Stimulated Effects in Cux(As2Se3)100-x Glasses

Through isoconversional analysis of differential scanning calorimetry data, thermally induced processes of glass transition and crystallization in Cu-x(As2Se3)(100-x) chalcogenide glasses (x =1, 5, 10, and 15 at.%) were investigated. The characteristic values of activation energy and its changes during the processes were calculated using the advanced isoconversional method developed by S. Vyazovkin as well as isoconversional forms of Kissinger and Moynihan relations. The results showed the variation of the activation energy with the extent of conversion. The activation energy values are slightly changing with the increase of Cu content from 1 to 5 at.%, while more significant changes are detected after a further increase of Cu content up to 15 at.%. The crystallization processes of As2Se3 in composition with 1 at.% of Cu and CuAsSe2 and Cu3AsSe4 in composition with 10 at.% of Cu were analyzed. Isoconversional analysis showed that crystallization is a complex process and that the apparent activation energy of crystallization of As2Se3 and CuAsSe2 structural units decreases with the extent of conversion increase.