PECULIARITIES ACCOMPANYING THE ENTHALPY RECOVERY DURING STRUCTURAL RELAXATION OF CHALCOGENIC GLASSES

Chemical short range ordering (CSRO) structural relaxation of slowly c ooled Ge10(Se85Te15) glass isothermaly and isochronally heat-treated i n the vicinity of glass transition region was studied by the use of di fferential scanning calorimetery. The recovery of excess enthalpy, DEL TAH(excess) (DELTAE(AES)), and of the temperature of maximum of the e xcess apparent specific heat, T(max) (DELTAE(AES)), plotted versus th e activation energy, DELTAE(AES) = RT(a) ln(nu0t(a)), showed unique m aster curves independent of annealing temperature, T(a), or annealing time, t(a). DELTAH(excess)(T(a), t(a)), which is proportional to the i nstantaneous degree of local order, alpha(T(a), t(a)), represents the true kinetic equation for the studied structural relaxation but the re lation between T(max)(T(a), t(a)) and alpha(T(a), t(a)) is not simple. From the DELTAH(excess)(DELTAE(AES)) master curve, isothermal and is ochronal relaxation effects consistent with experimental data were sim ulated. DELTAH(excess,t(a)=infinity)(T(a)) = const1 + const2/T(a) char acterizing the equilibrium of CSRO not reached in the experimental tim escale was determined.