The isothermal crystallization of three random copolymers of epsilon-caprolactone with different contents of 2,2-dimethyltrimethylene carbonate (DTC) (DTC: 5, 9 and 18 mol%) and poly(epsilon-caprolactone) (PCL) was studied using DSC and PLM methods. The isothermal crystallization data were analyzed with the Avrami equation. The exponent n, from 3 of PCL to 2 of P(82%CL-ran-18%DTC), suggests a change of crystal form. The crystallization rate was lowered by the addition of DTC units, which interrupted the perfect crystallization of PCL. (C) 2003 Elsevier Ltd. All rights reserved.