AbstractThe effects of different annealing time/temperature regimes on the thermal and crystalline behaviour of a series of statistical copolyamides (nylon 8/nylon 12), prepared by activated anionic polymerization of octanelactam/laurolactam (OL/LL), were determined by DSC, X‐ray (WAXS), density and viscosity measurements. The melting temperature and the heat of melting increased with annealing time and temperature. The results were correlated with the molar composition of the copolyamides and showed a gradual increase in percentage crystallinity with tim