SYNTHESIS AND PHOTOBEHAVIOR OF HYDROPHILIC ACRYLIC POLYMERS CONTAINING AZOBENZENE GROUPS

New hydrophilic photochromic polymeric systems containing side-chain a zobenzene groups were synthesized by radical copolymerization of 4-acr yloyloxyazobenzene with hydrophilic acrylic comonomers containing in t he side chain either amide or quaternary onium groups. In all cases co polymerization products characterized by an almost random distribution of monomeric units were obtained. On irradiation at 366 nm, azobenzen e-containing copolymers underwent trans-to-cis photoisomerization of t he side-chain azo groups and in all cases monoexponential decay of the 320 nm absorbance was observed. Copolymer properties were investigate d by DSC analysis, solubility measurements, UV spectroscopy and photoi somerization kinetics. The results obtained are discussed in terms of nature and content of hydrophilic comonomer and water content of the s olvent used. The possibility of photomodulating copolymer solubility i s also suggested.