Influence of residual mechanical constraint on the polarization in PMMA

The coupling of the Thermal Step Method (which gives the repartition of electrical field and space charges) and the Thermo Stimulated Depolarisation Current Method (which gives the energy level) is an efficient tool which allows one to follow with precision the setting and disappearance of dipole orientation (polarization) and space charges. Moreover it allows one to reveal minority carriers which could be masked by majority carriers, We focus attention on PMMA. This insulating material, because of its simplicity (isotropic, amorphous) allows us to give interpret the fundamental phenomena which govern space charges. We show the influence of residual mechanical constraint on the polarisation