NON-ISOTHERMAL KINETICS IN SOLIDS The precision of some integral methods for the determination of the activation energy without neglecting the temperature integral at the starting temperature

The integral methods, which are obtained from the various approximations for the temperature integral, have been extensively used in the non-isothermal kinetic analysis. In order to obtain the precision of the integral methods for the determination of the activation energy, several authors have calculated the relative errors of the activation energy obtained from the integral methods. However, in their calculations, the temperature integral at the starting temperature was neglected. In this work, we have performed a systematic analysis of the precision of the activation energy calculated by the integral methods without doing any simplifications. The results have shown that the relative error involved in the activation energy determined from the integral methods depends on two dimensionless quantities: the normalized temperature theta=T/T-0, and the dimensionless activation energy x(0)=E/RT0 (where E is the activation energy, T is the temperature, T-0 is the starting temperature, R is the gas constant).