New side-chain poly(methacrylate)s with azo moieties were prepared by free radical copolymerization, starting from methyl methacrylate (MMA) and some original azo-monomers. The chromophore content was evaluated from H-1-NMR spectroscopy and elemental analyses; all structures exhibited a high content of azobenzene units. UV Vis measurements have also supported this fact. Reactivity ratios for the methacrylate systems and their corresponding Q e values were calculated based on several initial feed compositions (MMA and the newly synthesized azo-monomers) using an integral method with its appropriate software. The polymers were also characterized by FTIR, SEC and DSC-TGA techniques. The coloured poly(methacrylate)s exhibited glass transition temperatures between 141 and 168 degrees C and thermal stabilities up to 306 degrees C.