Polyvinyl alcohol (PVA; molecular weight 17,000 g/mol) with additions of several different amounts of magnesium sulfate (molecular weight 246.945 g/mol) was prepared by the casting technique. The dc electric properties of these films were measured in different temperature ranges and the activation energy values as a function of different magnesium sulfate amounts were calculated. The dependency of dc electrical conductivity sigma(dc) at a certain temperature was found to fit the well-known equation sigma(dc) = [(1/R) x (t/A)] (Omega(-1) m(-1)). The temperature dependency of a,,, which suggested an electronic hopping conduction mechanism in a thermally assisted electric field, in addition to some theoretical mechanism were discussed. Also the values of activation energy as a function of different amounts of magnesium sulfate were investigated and it was found that the activation energy values for most samples increase with increased amounts of magnesium sulfate. On the other hand, the nonlinear coefficient parameter as a function of the different amounts of magnesium sulfate was investigated for all the prepared samples. (C) 2004 Wiley Periodicals, Inc.