COMMENTS ON THE ELECTROTECHNICAL AGING COMPENSATION EFFECT

In many cases of accelerated thermal ageing of polymers of electrotechmical interest, it has been found that for various Arrhenius lifelines, corresponding to various endlife criteria or various property measurements, there is a linear correlation between the logarithm of the pre-exponential factor and the activation energy. In the present work, an attempt is made to demonstrate that this phenomenon, which is named the compensation effect, cannot occur when the basic condition for the applicability of the Arrhenius law, namely the existence of a single mechanism controlling the change of properties, is respected. In contrast, there are various cases where the overall kinetics are only apparently Arrhenian (at least in a restricted temperature range) and where a pseudo compensation effect can be observed. Some numerical examples are discussed.