<title>Physical significance of the compensation behavior associated with glass transition relaxation as observed by thermally stimulated currents</title>

Abstract

The present communication deals with the study of the (alpha) -relaxation in amorphous polymers using the technique of thermally stimulated depolarization currents. In this context, the physical significance of the so-called compensation point is discussed. Experimental results are compared with the predictions based on the hypothesis of the existence of the compensation point. It is concluded that a strong increase of the activation enthalpy is observed when the glass transition temperature is approached on heating, which is accompanied by a concomitant increase of the activation entropy. This behavior, often called compensation behavior, seems to be a real feature of the (alpha) - relaxation in amorphous polymers. Nevertheless, the compensation point seems to be an artifactual consequence of mathematical manipulation, so that its coordinates, (tau) <SUB>c</SUB>, T<SUB>c</SUB>, lack any physical significance and can not be related to any material property.