Up to now, few techniques were available that allowed nondestructive in situ characterization of polymerization during the curing of a thermoset resin. Dynamic dielectric measurements made over a wide range of frequencies provide a sensitive and convenient control to follow up the epoxy-amine cure or to follow the formation of the thermoplastic materials. The direct current measurements and the time of flight measurements were developed to confirm interpretation of the electrical techniques in terms of correlations of the evolution of the conductivity and the network formation and also to evaluate the real value of the ion mobility and its evolution in a course of reaction.