Preparation and photochromism of carboxymethyl chitin derivatives containing spirooxazine moiety

A novel water-soluble photochromic polymer 4 was prepared by graft copolymerization of 9′-allyloxyindolinospiro-naphthoxazine 3 onto carboxymethyl chitin (CMC) and characterized by IR, etc. The photochromism has been studied by UV–vis spectroscopy. Polymer 4 has not only shown water solubility but also usual photochromic behavior. Compared with the acetone solution spirooxazine 3, the thermal stability of open-form of polymer 4 has been improved significantly.