The effect of glass transition temperature of acrylic polymers containing spiropyran on photo-isomerization rate

Several photochromic polymers containing spiropyran were prepared and irradiated by UV-Vis light and in order to investigate the effect of glass transition temperature of polymer matrix on the kinetics of the photoisomerization of the obtained functionalized latex nanoparticles. The samples were prepared by semicontinuous emulsion polymerization with a constant amount of spiropyran ethyl acrylate and varying ratios of methyl methacrylate to butyl acrylate. TEM micrographs showed spherical morphology of the obtained nano particles below 100 nm in size and this was confirmed by DLS analysis. The rate of photo-isomerisation was measured by kinetic studies and it was found that the sample containing 60 wt% of butyl acrylate showes fastest isomerization rate.