The preparation of a block copolymer of methyl methacrylate (MMA) and vinyl acetate (VAc) (PMMA-b-PVAc) was carried out by successive charge-transfer polymerization (CTP) in aniline-benzophenone as binary initiation system under ultraviolet irradiation; subsequently a block copolymer of PMMA and poly(vinyl alcohol) (PMMA-b-PVA) was derived by selective hydrolysis of PMMA-b-PVAc in ethanolic sodium ethoxide. These copolymers were characterized in detail by means of Fourier transform infra-red and proton nuclear magnetic resonance spectroscopies, and gel permeation chromatography. The solvent polarity exerts an effect on the copolymerization.