Dielectric properties above the glass transition temperature (T-g) have been investigated for three bisphenol-A novolac type epoxide oligomers (PGEBANs) that have some branching in each molecule in comparison with the diglycidyl ether of bisphenol-A (DGEBA) oligomer without branching. The relationship between the dielectric relaxation time (tau) and T-g for the branched PGEBAN oligomers is expressed by a modified Williams-Landel-Ferry (WLF) equation taking T-g as a variable at fixed temperatures from 70 to 100 degrees C. The WLF-type relationships between tau and T-g for the two types of uncued epoxide oligomers, the branched PGEBAN and the nonbranched DGEBA, were found to be useful for predicting the T-g of a branched DGEBA-alicyclic amine system during the middle stage of curing.