In the Present Study, the effects of charge-transfer complex formation and intra molecular fragmentation (side-chain lactonization) in radical copolymerization of terf-butyl vinyl ether (t-BVE) with anhydrides of maleic (MA) and citraconic (CA) acids and the structure-thermal behavior relationships of the resulting copolymers were examined using the H-1-NMR, FTIR, DSC, and TGA analysis methods. It was shown that copolymerization under the chosen conditions proceeded through intramolecular fragmentation with the formation of gamma-lactone units. Side-chain fragmentation of t-BVE-MA and t-BVE-CA copolymers also was confirmed by TGA and DSC analysis. (c) 2006 Wiley Periodicals, Inc.