Radical copolymerization of di(isobutoxy)methylvinylsilane 1 and di(isobutoxy)phenylvinylsilane 2 with methyl methacrylate (MMA) and n-butyl acrylate (n-BA) was carried out, and the oxidative cleavage of Si-C bonds in the resulting copolymers was examined to prepare copolymers having repeating units of vinyl alcohol (VA). Although the incorporation of 1 and 2 in the copolymerization of these alkoxyvinylsilanes with MMA was not so effective (1 or 2 content < 18 mol%), MCPBA-induced oxidative transformation of a poly(2-co-MMA) with 9.0 mol% of 2 content proceeded efficiently, giving a poly[(vinyl alcohol)-co-MMA]. On the other hand, whereas poly(1 or 2-co-n-BA)s with relatively higher 1 or 2 contents (up to 45 mol%) can be prepared by the radical copolymerization of 1 or 2 with n-BA, oxidation of the copolymers afforded insoluble products.