Spectroscopic and photophysical properties of salicylaldehyde azine (SAA) as a photochromic Schiff base suitable for heterogeneous studies

The photochromic cycle of the salicylaldehyde azine (SAA) has been investigated by means of the stationary and time-resolved UV–vis spectroscopy in a number of differently interacting solvents and micellar systems. The primary enol form of this Schiff base is much more energetically stabilized than in the other aromatic Schiff bases, which is reflected in remarkable resistance of SAA to the hydrolysis process. The fluorescence decay measured in highly viscous solvents as well as in micellar systems has proved the existence of different conformers of the cis-keto tautomer. Three different routes of the photochrome (trans-keto tautomer) decay have been also observed.