Infrared spectroscopy is a fine tool with which to experimentally explore the effect of chainconnectivity and functional group accessibility in hydrogen-bonded polymer blends. Such factors directlyaffect the fraction of intermolecular hydrogen-bonded groups that are formed and effectively reduce thehydrogen-bonding contribution to the free energy of mixing vis-à-vis analogous low-molar-mass analogues.In this study we report the results obtained from blends of copolymers containing vinyl cinnamate (VCIN)with copolymers containing 4-vinylphenol. The VCIN segment undergoes facile photocross-linking uponexposure to UV radiation, permitting the effect of cross-linking on functional group accessibility andphase behavior to be studied.