ABSORBED WATER IN THE CORK STRUCTURE - A STUDY BY THERMALLY STIMULATED CURRENTS, DIELECTRIC-RELAXATION SPECTROSCOPY, ISOTHERMAL DEPOLARIZATION EXPERIMENTS AND DIFFERENTIAL SCANNING CALORIMETRY

This paper reports on a modification of the dielectric properties of c ork which occurs as a consequence of heating above 60 degrees C or eva cuation for several days. This phenomenon was observed using different experimental techniques (thermally stimulated currents, dielectric re laxation spectroscopy, isothermal depolarization experiments and diffe rential scanning calorimetry), and the corresponding kinetics were ana lysed. It was observed that the original properties of co rk were reco vered if the sample was exposed to room air for several weeks. It is s uggested that the reported modification of the dielectric properties a rises from desorption, induced by heating or evacuation, of water mole cules absorbed in the cork structure.