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The study of glycolide (GL) and ethylenoxalate (EO) copolymerization with the use of SnCl2 2 H2O as a catalyst was carried out by 1H NMR spectroscopy. Monomer reactivities are found to be close and equal to 1,1 and 1,11 for GL and 0,71 and 0,85 for EO at 150 and 170 °C, respectively. Kinetic data obtained show that the reaction proceeds without induction period up to entire consumption of every monomer. The detailed identification of 1H spectra enables to follow the polymer microstructure in the course of copolymerization. Thermal properties of copolymers and their biodegradation abilities have been studied. The biodegradation rate is shown to increase with growing EO proportion in the copolymer. The lactone biodegradation mechanism where the electrophility of carbon and nucleophility of OH group are playing the most important role, is suggested. The correlation between the biodegradation rate and the chemical shift in 13C NMR spectra of the carbon atom of the carbonyl group has been established.

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