The relaxation parameters and their distributions deduced from thermally stimulated discharge current

In the analysis of thermally stimulated depolarisation current, the results obtained when it is assumed that only one parameter, either the activation energy W or the pre-exponential factor /spl tau//sub 0/ is variable, are different. The peak position and shape change significantly when, for a simulation, it is assumed that the activation energy is variable and the pre-exponential factor is constant or vice versa. An improved expression for the current is proposed that takes into consideration that W and /spl tau//sub 0/ change simultaneously. The distributions in activation energies and in preexponential factors cannot be determined properly if /spl Delta/W/spl cong/kT/sub m/ and /spl Delta//spl tau//sub 0//spl cong//spl tau//sub 0/, or by assuming only one distribution.