ACIDICHROMISM OF INDOLINOSPIROOXAZINES IN ISOPROPANOL

indolino-2,3'-[H-2]naphtho[2,1-b][1,4]oxazine(SP1) and 1,3,3-trimenthy l-9'-methoxy-spiro[ indolino-2,3'-[2H]naphtho[2,1-b][1,4]oxazine](SP2) react with hydrochloric acid to form the complex SP . HCl in isopropa nol solution at room temperature. The absorption maxima of these compl exes are 440 and 463 nm respectively. In acidic media, the opening for m of spirooxazine can react with hydrochloric acid to form the complex PMC . HCl via zwitterion form. The absorption spectra of PMC . HCl ar e obviously hypsochromic shifted compared with the reported spectra of the complex in neutral media. In the mean rime, the thermal stability of the complex is increased. The first order kinetics for the decolor ation process of the acidichromic product of the opening form was dete rmined and the lifetimes of these products are 180 and 200 s, respecti vely.