4-Phenylazoacrylanilide (1), 4-phenylazomethacrylanilide (2) and N,N-dimethylazoanilineacrylanilide (3) were prepared by a phase transfer acylation method. Compound 3 had not been reported previously in the literature. Copolymers of 1, 2 and 3 of various feed ratios were prepared with methyl methacrylate, styrene and methyl acrylate as well as homopolymers of the azo-monomers. The preparation of methyl acrylate copolymers with azo-monomers had not previously been attempted, from our reading of the literature. Studies of the kinetics of photoisomerisation and thermal isomérisation of the azo-monomers in solution and the copolymers in solution and the solid state were undertaken. The activation energies and associated thermodynamic parameters were calculated for the thermal isomérisation using the Arrhenius and Eyring equations. For the solid state thermal isomérisation studies it was found that two distinct first order cis to trans isomérisations occurred; a normal reaction, as in solution, and an anomalously fast reaction. It was found that for series of methyl methacrylate and styrene copolymers, the normal reactions were similar, but the anomalously fast isomérisations were significantly different. Dependence of the relaxation mechanism on chemical structure, rather than on physical surroundings had not been previously reported. Treatment of the kinetic data using the Williams, Landel and Ferry equation for behaviour of solid state polymers in the region of the glass transition temperature, confirmed this observation. The normal cis to trans isomérisation for poly{4-phenylazoacrylanilide) (7) and poly(4- phenylazomethacrylanilide) (8), and for the crosslinked copolymers (4e and 4g) also differed significantly from that of the other copolymers. Possible reasons for these differences are discussed.