The kinetics of water absorption in epoxide materials was studied by the aid of a diglycidyl ether of bisphenol-A-triethylenetetramine (DGEBA-TETA) epoxyresin system containing various amounts of the plasticizer THIOCOL (0 -40 phr). The presence of plasticizer permits the formation of products with different crosslinking densities and hydrophilic characters. Dynamic water absorption experiments were carried out at 15, 40, and 70Β°C. For the fitting of the experimental results, a new model was used, based on a model proposed earlier by Jacobs and Jones. This model considers epoxide product as a two-phase system consisting of a master phase (where the major part of the water is absorbed), which is homogeneous and nonpolar (phase 1), and of a second phase with different density and/or hydrophilic character (phase 2). By making the assumption that water diffusion can take place independently in the different phases of the material in accordance with Fick's second law, we can calculate the diffusion coefficient D and the water content at saturation M Ο± for each phase separately. Equilibrium water sorption measurements were performed at 40Β°C, and the data were analyzed and discussed based on the Guggenheim-Anderson-de Boer (GAB) equation, the results being in support of the two-phase model used in the analysis of absorption kinetics. The linear expansion coefficient and the glass transition temperature of the materials, employed in the discussion of the results, were measured by thermomechanical analysis.