Isothermal crystallization of poly(butylene naphthalene-2,6-dicarboxylate) (PBN), from the melt, at various crystallization temperatures ranging from 213 up to 225 degreesC was studied. During isothermal crystallization, relatively high crystallinity was found to develop. Isothermal crystallization kinetics was studied using the Avrami equation. For non-isothermal studies, PEN was crystallized by cooling rates ranging from 0.5 to 20 degreesC/min. Only semicrystalline PEN was produced, not depending on the cooling process. The Ozawa and modified-Avrami approaches were used to describe the non-isothermal crystallization kinetics of PEN. Recrystallization phenomena and multiple melting peaks were observed during heating of isothermally and non-isothermally crystallized samples. Annealing at temperatures very close to the original melting point increased the latter from 248 to 264 degreesC. (C) 2000 Elsevier Science Ltd. All rights reserved.