Conformational changes are sought during low-temperature ageing of solution-cast films of BPA-polycarbonate, by observing the conformationally sensitive IR aromatic breathing band at 1600 cm(-1). Preliminary results using the carbonyl band at 1775 cm(-1) had shown some indication of ageing-induced changes in the distribution of conformations. The present results obtained on the 1600 cm(-1) band show no indication whatever of conformational rearrangements. This result, at variance with observations of conformational rearrangements accompanying sub-T-g annealing, lends support to the concept that sub-T-g annealing and low temperature ageing are two distinct processes.