The kinetics of catalysed and uncatalysed acidolysis between hydroquinone diacetate-terephthalic acid (HT), hydroquinone diacetate-isophthalic acid (HI) and resorcinol diacetate-terephthalic acid (RT) were investigated at 280, 290, 300, 310 and 320 degrees C. Two kinetic regimes were observed in the rate law plots. Kinetic behaviour in the two regimes differed with the system. Simple second order rate law describes the initial stage kinetics of these reactions most adequately. Activation energy estimates indicate the presence of compensation effect in RT system. Oligomers isolated from HT and HI polyester samples display thermotropic character.