Rapid fading of 3H-naphtho[2,1-b]pyrans with protonation of N,N-disubstituted group

Abstract

We present the rapid fading of photochromic 3H-naphtho[2,1-b]pyrans at ambient temperature by protonation of N,N-disubstituted group. It is found that photochromic 3H-naphtho[2,1-b]pyrans with a N,N-disubstituted group are converted to protonated 3H-naphtho[2,1-b]pyran by treatment with acid, and the protonated 3H-naphtho[2,1-b]pyrans show rapid fading in both solution and a rigid polymer matrix at ambient temperature. It is also found that the protonated 3H-naphtho[2,1-b]pyrans exhibit similar absorption and fatigue resistance compared to their original compounds.