Normal and Reverse Photochromism of 1-(β-carboxyethyl)-3,3-dimethyl-6′-nitrospiro[indoline-2,2′-2<i>H</i>-benzopyran] in Water–Dioxane

Abstract

Abstract The photochromism of 1-(β-carboxyethyl)-3,3-dimethyl-6′-nitrospiro[indoline-2,2′-2H-benzopyran] (I) was studied in water-dioxane. It was found that (I) exhibits normal photochromism in dioxane and reverse photochromism on addition of water to the solution.