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We have compared measurements of a set of polyethylene terephthalate (PET)electret samples by means of pulsed electroacoustic method (PEA) and thermallystimulated depolarization current (TSDC) techniques. Experimental parameterssuch as the combined thermal and electrical history and the electrode type havebeen selected in order to correlate the polarization mechanisms revealed byTSDC with the charge profile measured by PEA in five different cases. Existingdeconvolution procedures for PEA have been improved as a means to enhance thecalibration of PEA signals in the case of thin samples. Samples where the$\alpha$ dipolar relaxation or the $\rho$ space charge relaxation is activatedshow a uniform polarization that manifests itself as image charge at theelectrodes. In the experiments where external charge carriers are injected intothe sample, the same poling procedure has been tested under different electrodeconfigurations. Charge profiles are qualitatively similar in all of them butthe depolarization currents show clearly different behavior. These differencesare explained, on the one hand, by the different blocking behavior ofvacuum-deposited aluminum electrodes with regards to electrodes with a thin airgap and, on the other hand, by the distinct behavior of electrodes with an airgap for both directions of the charge carriers. Numerical analysis of thepolarization of TSDC peaks and charge per unit area of charge profiles supportsthis interpretation and confirms the relationship between both measurementtechniques. All in all, PEA in combination with TSDC turns out to be a usefultechnique in the study of thermally poled electrets, either in the study ofrelaxations or of external charge.

Comparison of pulsed electroacoustic and thermally stimulated depolarization current measurements of thermally poled PET electrets