The alternating copolymer of allyl acetate and maleic anhydride has been prepared by the free radical route at 60 o C. Temperature ranges of decomposition under programmed heating have been determined by thermogravimetry and thermal volatilisation analysis (TVA). The TVA method has also been used to establish the amounts of the main product fractions in terms of volatility. The largest fraction comprises volatile gases and liquids and these have been characterised by IR spectroscopy, mass spectrometry and GC-MS, the most important components being acetic acid and carbon dioxide. Temperature regions for production of the most important volatile products have been established by MS selective ion monitoring during the degradation. The principal consitituents of the tar/wax product fraction have also been characterised. Unlike the alternating copolymers of maleic anhydride with vinyl acetate and isopropenyl aectate, respectively, the allyl acetate copolymer shows some decomposition of the maleic anhydride units before acetic acid is released. Extensive fragmentation of the modified chain structure, however, does not occur below 350 o C.