A supported epoxy-imide adhesive has been aged in air at elevated temperatures (180-250 degrees C). Evolution of the material has been studied using gravimetry, optical microscopy, X-ray microanalysis, and viscoelasticimetry. Mass loss was manifest and has been shown to be more significant from adhesive surfaces exposing fibres (the support) than from those presenting only polymer. Microscopic examination and X-ray microanalysis indicated the formation of oxidised regions near the exposed surfaces of the polymer. Regions with exposed fibres degraded more rapidly due to facilitated oxygen ingress. This surface governed form of degradation seems to be accompanied by bulk thermolytic ageing, not requiring oxygen, as shown by viscoelasticimetry, indicating a drop in the glass transition temperature, T-g, after ageing. (C) 2000 Elsevier Science Ltd. All rights reserved.