Relaxation time distribution from time and frequency domain dielectric spectroscopy in poly(aryl ether ether ketone)

A new application of the simulated annealing Monte Carlo procedure is prese nted and applied to the extraction of the relaxation time distribution from dielectric spectroscopy either in time or frequency domain. This decomposi tion method named simulated annealing direct signal analysis (SADSA), is ap plied to computer generated curves, epsilon(t), epsilon'(omega), and epsilo n'(omega), by using the most widely accepted empirical distributions. The d iscretized distribution fits exactly the analytical expression which can be evaluated in these cases for the set of parameters used in the simulation. Also, both distribution functions are found to be identical which proves t hat the method is certainly converging to the right solution in both cases. Experimental results on amorphous poly(aryl ether ether ketone) for epsilo n(t), epsilon'(omega), and epsilon'(omega) are analyzed with SADSA and the obtained relaxation time distribution is used to go from time to frequency domain and reciprocally. The results are compared to those obtained by assu ming a Havriliak-Negami profile for the distribution function. (C) 2000 Ame rican Institute of Physics. [S0021-9606(00)50226-8].