STRUCTURAL RELAXATION AND ANHARMONICITY IN POLYMER ELECTROLYTES - EFFECT OF THE THERMAL HISTORY

The effects of the storage at room temperature of PEO-KSCN polymer ele ctrolytes have been studied by differential scanning calorimetry (DSC) and dynamical mechanical analysis. It has been revealed that, over th e explored time interval, the annealing causes small variations in the anharmonic and relaxation properties of the samples, which are to be ascribed to changes in the relative amount of the phases building up t he structure. The elastic and anelastic characteristics show a well-de fined dependence on the degree of crystallinity of the polymer, which grows slightly with increasing annealing time. The application of a si mplified version of a quasi-harmonic model and of the Kolrausch-Willia ms-Watts stretched exponential function permits to describe the temper ature behaviour of the elastic modulus E' and to obtain an anharmonici ty parameter characterizing the polymeric system.