Comparison of analysis of dielectric spectra of PCL in the ε* and the M* formalism

The complex dielectric modulus, M*(omega, 7), for poly(epsilon-caprolactone) has been obtained by inverting the complex dielectric permittivity data, epsilon*(omega, T) recorded in a wide temperature and frequency range. The analysis of the dielectric loss modulus spectra M(omega, 7) have been performed by using a simulated annealing Monte Carlo procedure in order to extract the relaxation parameters for each relaxation mode. Besides the local modes gamma and beta, the segmental alpha mode associated to the glass transition, the conductivity and the interfacial polarization peaks could be analyzed with a better precision than by using the conventional non-linear least squares method in epsilon domain. The merging of the alpha and beta modes at high temperatures is much better defined due to the less significant contribution of the ionic conductivity in M* formalism. (c) 2007 Elsevier B.V. All rights reserved.