Two chemical structural isomers, 2-hydroxyethyl methacrylate and ethyl alpha-hydroxymethyl acrylate, were copolymerized with dimethyl amino ethyl methacrylate in bulk at 50 degreesC with 1.0 X 10(-2) mol/L 2,2'-azobisisobutyronitrile as an initiator. Experiments showed differences in the values of the monomer reactivity ratios due to electronic or steric contributions to the cross-propagation reaction. The homopolymer glass-transition temperature (T-g), along with the intramolecular and intermolecular structure and Johnston's equation, enabled a description of the experimental variations of the copolymer T-g. (C) 2003 Wiley Periodicals, Inc.