INTERCONVERSION MODEL FOR MECHANICAL AND DIELECTRIC α-RELAXATIONS MEASUREMENTS

This work describes a new algorithm of interconversion between mechanical and dielectric measurement. Another version of this algorithm has been proposed in a previous paper [1], starting from a scaling relation between the translational and rotational viscositieś, which is assumed in a glass forming liquid near the glass transition temperature.In order to improve the previous procedure, the following modifications have been made: 1) a new definition of the complex rotational viscosity in terms of a fractional power, 2) the complex translational viscosity is taken as a non‐Newtonian one, 3) the modulus and phase angle of viscosities were analyzed instead of real and imaginary viscosities and 4) the characterization of the α dielectric relaxation has been carried out by means of the dielectric retardation time spectrum.It is usual that the α and secondary relaxation processes are overlapped in the dielectric and mechanical spectra. Both types of processes have distinct physical basis and different molecular dynamic. For this reason, in the calculation of the mechanic properties using dielectric measurement, and vice versa, it is necessary to consider the α‐ relaxation band separated from the secondary one.