In this work, the activation energies of crystallization of amorphous Sb9.1Te20.1Se70.8 have been studied under non-isothermal conditions using a differential scanning calorimetric (DSC) technique. The analysis focuses on the effect of temperature (413 <= T <= 437 K) on the DSC results. The three isoconversional methods of Friedman, Kissinger-Akahira-Sunose (KAS) and Vyazovkin were used to determine the variation of the activation energy for crystallization with temperature, E-alpha(T). The KAS and Vyazovkin methods gave identical values, and the range of E-alpha(T) was found to vary from 128.7 down to 77.8 kJ mol(-1), while the Friedman method gave lower values with E-alpha(T) from 84.1 to 31.2 kJ mol(-1). The effects of annealing were revealed by studying the morphology of the samples using scanning electron microscopy. (c) 2007 Elsevier B.V. All rights reserved.