Abstract: Two novel cationic indolinospirpoyrans, 1′-(n-butyltriethylammonium iodide)-3′,3′-dimethyl-6-nitro-8-methoxyspiro[2H-1-benzopyran-2,2′-indoline] and 1′-(n-butyltriethylammonium iodide)-3′,3′-dimethyl-6,8-dinitrospiro[2H-1-benzopyran-2,2′-indoline], were synthesized and characterized by suitable methods. The structures and configurations of MC and SP of the two compounds are assigned via their 1H NMR spectra. The photochromism properties of the two compounds were investigated. It was found that the former one shows normal photochromism and the later one shows negative photochromism. The decoloration and coloration process of the two compounds fit first-order kinetics very well, and their rate constants are 1.21×10^-2s^-1 and 4.0×10^-5s^-1, respectively.

Key words: indolinospiropyran, normal photochromism, negative photochromism