One of the disadvantages of using polymers for outdoor applications is the photo-degradation which deteriorates their mechanical properties eventually leading to structural failure. Therefore, rather than a loss of mechanical properties in polymer structures under UV exposure, it would be an accomplishment if the mechanical properties could be enhanced to improve the structural integrity of polymeric structures. This study examines the photomechanical property enhancement in a series of photo-responsive copolymers of methyl methacrylate and methacryloyloxy azobenzene (MOAB) with azobenzene chromophores in the side chains, using nanoindentation. We assume the effect of chromophore concentrations enhances the photomechanical properties. We found that a maximum increase in stiffness of 19% can be achieved with an optimum loading of 30% mol azobenzene. Such an enhancement in stiffness was attributed to photoinduced reorganization of the polymer chains due to the isomerisation of the azobenzene chromophores. UV/Vis spectroscopy of the polymer films suggested that the trans isomer of azobenzene was converted to the cis form within 7 min of exposure to UV light, whereas the reversion from the cis to the trans isomer was achieved within 1 min by visible light. Analysis of the indented thin films by optical microscopy demonstrated healing of the indented region by UV light suggesting that this polymer can be used as self-healing material. (C) 2015 Elsevier Ltd. All rights reserved.