Solid State Ionics, Vol.105, No.1-4, 167-173, 1998
The dielectric modulus : relaxation versus retardation
Experiments which access the quantity epsilon*(omega) are usually termed dielectric relaxation methods, although epsilon*(omega) and epsilon(t) actually refer to dielectric retardation. The true dielectric relaxation, the modulus M(t), corresponds to the decay of the electric field under the conditions of a constant dielectric displacement. We have measured the polarization in terms of a real dielectric relaxation technique by studying the decay of the electric field E(t) proportional to M(t) for times 10(-3) s less than or equal to t less than or equal to 10(6) a under constant charge conditions. This conceptually straightforward method bears the advantage of the ability to measure extremely large retardation times. Using the equivalent thermally stimulated technique we also investigate the equilibrium and non-equilibrium dynamic response of amorphous condensed matter well below its caloric glass-transition.