Measurement and analysis of time-domain electric field relaxation: The vitreous ionic conductor 0.4Ca(NO3)(2)-0.6KNO(3)

We have measured the electric modulus M(t) of the ionic conductor 0.4 Ca(NO 3)(2)-0.6 KNO3 (CKN) by recording the electric field relaxation E(t) under the constraints of a constant displacement D-0. The vitreous material CKN i s studied in its glassy state for temperatures 240 K less than or equal to T less than or equal to 330 K and for times 7x10(-3) s less than or equal t o t less than or equal to 3x10(5) s. In this range the dc conductivity vari es from 3x10(-11) to 5x10(-17) S/cm according to Arrhenius behavior. We sho w that the time dependent resistivity rho(t), instead of the conductivity s igma(t), is an appropriate quantity for assessing the time dependent and st eady state effects of ionic diffusivity on the basis of experimental modulu s data M(t) recorded in the time domain. Even substantial electrode polariz ation is not critical with regard to this data analysis. (C) 1999 American Institute of Physics. [S00218979(99)03003-0].