We consider how nanoparticles affect molecular photoswitches and our focus is on how the polarizabilities and hyperpolarizabilities of the dihydroazulene/vinylheptafulvene system changes, when the compounds interact with gold nanoparticles. We have utilized a combined quantum mechanical/molecular mechanical approach, where the photochromic molecule is described by time-dependent density functional theory using the long-range-corrected CAM-B3LYP functional and the correlation consistent aug-cc-pVDZ basis-set. The nanoparticles are described by gold atoms having an atomic polarizability. The calculations showed that the polarizabilities of the photochromic molecules are affected by the gold nanoparticles, but the hyperpolarizabilities change significantly as the interactions between the nanoparticles and the photochromic molecules are increased.