Surface relief grating formation was investigated for a series of azobenzene containing polymers with varying molecular weight. The polymers were obtained by a combination of an atom transfer radical polymerization of trimethylsilylethyl methacrylate and subsequent polymeranalogous introduction of the azobenzene chromophore. Irradiation of the polymers with interfering polarized laser beams resulted in the formation of surface relief gratings. The modulation depth of the gratings as measured by AFM decreases with increasing molecular weight, however, the effect is much smaller than expected.