We report a study of the curing mechanism of C-13 labelled bisphenol A dicyanate ester in the presence of a electrolytically surface treated XAS carbon fibre using several techniques - solid state C-13 NMR, scanning electron microscopy (SEM) and diffuse reflectance FTIR. Comparison of the results obtained in pure matrices and solution shows that the resin undergoes the same reaction mechanism in both cases and forms the sym-triazine network structure in the composite.