The crosslinking reaction of poly(vinyl alcohol) (PVA) with 3,3’,4,4’-tetracarboxybenzophenone dianhydride, pyromellitic carboxylic acid anhydride, and Epiclon B-4400 as hardeners was studied either in solution or by differential scanning calorimetry. A catalyst agent had to be used in all cases. Depending on the concentration of hardener and catalyst, differences are observed. T-g values increase with the ratio of hardener and catalyst, while activation energies decrease with the amount of catalyst but little changes can be seen when different dianhydride amounts are used. The thermal properties of the final products were unaltered by the hardener used. The decomposition temperature is initiated at a similar temperature in linear and crosslinked PVA, but while uncured PVA undergoes a complete degradation in one step, crosslinked PVA degrades in several steps.