Opening the way to greener photochromic and fluorescence studies by using the 6-NO2-BIPS photoswitch

Abstract

This article investigates the photochromic and fluorescence response of the spiropyran-derived 6-NO2-BIPS photochrome in different media using a green chemistry approach. A red fluorescence emission of the coloured form was observed in all the tested media. The spontaneous back-reaction of the UV-irradiated compound was studied by absorption spectroscopy in 2-Me-THF [t(1/2) = 19.7 s], cyclopentyl methyl ether (CPME) [t(1/2) = 12.6 s] and a water/ethanol/SDS solution [t(1/2) = 146 min]. The latter was found to enable quasi-P type photochrome behavior. Drop-casted and spin-coated thermoplastic polyurethane films were prepared at 1 and 2 mass percentages of 6-NO2-BIPS as a dopant. The films could offer promising results, especially in applications mimicking photochromic glass behavior.