Polymeric epoxides can be converted to corresponding five-membered cyclic carbonates effectively by the reaction with carbon dioxide. For instance, poly(glycidyl methacrylate) (PGMA) was quantitatively converted to a polymethacrylate bearing a five-membered cyclic carbonate group (PDOMA) by the polymer reaction with carbon dioxide using alkali metal or quaternary ammonium halide salt as a catalyst. The salts having more Lewis acidic cation and more nucleophilic anion acted as more effective catalysts. Kinetic analyses of the polymer reaction show that the reaction rate can be expressed by the empirical equation : -d[epoxide]/dt = k[epoxide][catalyst](m), where m depends on the Lewis acidity of the catalyst and molecular weight of the epoxide. The rate of the reaction is independent of the pressure of carbon dioxide. Further, various polymeric epoxides such as GMA copolymers, poly(glycidyl acrylate), and poly(vinylbenzyl glycidyl ether) could be converted to the corresponding polymers bearing five-membered cyclic carbonate moieties by the reaction with carbon dioxide, whereas the presence of an aromatic group in the structure of the polymer could retard the reaction with carbon dioxide.