Evaluation of activation energy of thermally stimulated solid-state reactions under arbitrary variation of temperature

The thermal effect of a reaction makes the temperature inside the reaction system deviate from a prescribed heating program. To take into account the effect of such temperature deviations on kinetic evaluations, a computational method applicable to an arbitrary variation in temperature has been developed. The method combines the isoconversional principle of evaluating the activation energy with numerical integration of the equation, dα/dt = k[T(t)]f(α), over the actual variation of the temperature with the time, T(t). Details of the numerical algorithm are reported. A model example has been used to verify the reliability of this method as compared to an analogous method which does not account for the deviations of the temperature from a prescribed program. The method has been tested for tolerance for noise in the temperature. © 1997 by John Wiley & Sons, Inc.