Thermally stimulated discharge polarization temperature

The previous section reviewed the advances of what may be termed the classical technique of dielectric spectroscopy, which has, as its modes of operation, measurements either at constant temperature or at constant frequency. Recently a technique which does not operate with these restrictions has been developed, particularly by van Tumhout This technique is variously termed thermally stimulated discharge (TSD) or thermally stimulated current (TSC). In its simplest form a material in the form of a disc with electrodes in intimate contact on opposite faces is heated to some forming temperature Tf. At this stage the sample is polarized by applying a strcsng electrostatic field ( 30 kV/cm) for an extended period. All polarization processes which are active at, or below the tenqjerature Tf and within the time the fidd has been on, will contribute to an overall polarization the material within the field is polarized. If the field were now removed at the temperature Tf, the polarization could be disdiarged as in the step response technique of the previous section. However, in TSD the temperature is reduced to some value < Tf with the field still on. Any polarization process which is non-active at but active between and Tf has thereby been frozen-in at T < Tg, even when the field is removed as in the TSD tech-... 

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