Acidichromic effects in spiro(1,3,3-trimethylindolo-2,3'-naphth[1,2-b]-1,4-oxazine), a photochromic compound .1. Absorption characteristics

Acidichromic and photochromic effects in alcoholic solutions of spiro(1,3,3-trimethylindolo-2,3'-naphth[1,2-b]-1,4-oxazine) are described. First-order, thermally-initiated decay kinetics associated with relaxation of the merocyanine form under acidic conditions are reported. A model for acidichromic and photochromic processes in these systems has been proposed. Preliminary results indicate that spirooxazine compounds are potentially useful in device applications such as pH sensors.