Determining Temperature Dependence of Dielectric Response by Temperature Normalization Method

Abstract

Temperature is a significant external influence of dielectric response which almost always influence the characteristic relaxation frequency. These different effects can be most easily be revealed by the temperature normalization method of plotting the data from different temperatures. This method consists in shifting the dielectric response measured at different temperature into coincidence, by which the ‘master curve’ is determined. The physical significance of temperature normalization method is to describe the relationship between the temperature and spectral shape function of dielectric response (the spectral shape function describes the relationship between dimensionless frequency and dimensionless susceptibility, which directly relates to the micro-structure of dielectric). In order to obtain the correct master curve, the temperature normalization method should be carried out in log-log plot by shifting the real and imaginary components of dielectric response simultaneously. Logarithmic axes are used because translations along them are the same as changing the frequency and amplitude by a multiplicative factor, i.e. the frequency and amplitude become scaled. The locus of the reference point in the translation process should also be recorded in detail, because it defines the relationship between inverse characteristic (relaxation) frequency and inverse amplitude as a function of temperature, which becomes a hidden variable. In this paper, the master curves of dielectric response of HTV silicone rubber is constructed to explain and to demonstrate the relevant issues in the application of the temperature normalization method in the analysis of dielectric response.