Two samples of bisphenol-A based epoxy resins (poly(hydroxy ethers)) were fractionated by precipitation. The fractions were characterized by the weight-average molecular weight (1.3 < M-w 10(-3) < 40) and the intrinsic viscosity in tetrahydrofuran and chloroform. Theories based on the worm-like touched-bead model were used to treat the molecular-weight dependence of the intrinsic viscosity and to estimate the conformational characteristics (Kuhn statistical segment length l(K), Flory characteristic ratio C-infinity, and steric factor sigma). Low values of these characteristics indicating rather high flexibility of the chain are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.