An electrical aging model including Kramers friction, phonon vibrations and electrostriction

In this paper, we show that the field-induced electromechanical stress cannot be the Maxwell stress, as we had assumed in former models. In fact, high field electrical aging seems to be another case of electrostriction. This does not change the more or less linear relation between log time and the square of the applied field but the activation volume (i.e. the inverse of the broken C-C bonds concentration) is significantly smaller. The activation energy is composed of several terms (as previously discussed) including the C-C bonds strength, the phonons free energy associated with molecular relaxations and a configurational entropy change. Below the isokinetic temperature of the given relaxation, a Kramers friction term must also be added. It also appears that at low fields the configurational entropy change is decreasing with increasing field up to the so-called threshold field. Further work is suggested.