Emission properties of a Reversacol spirooxazine have been investigated in microcrystalline solid phase and in poly( methyl methacrylate), PMMA, films. Emission spectra and lifetimes of the fluorescent states have been determined using steady state spectrofluorimetry and time-correlated single-photon counting techniques, respectively. Dual fluorescence, previously detected in solution, was also observed in microcrystalline phase and in PMMA. Fluorescence relaxation kinetics were analyzed by non-linear least-squares method and Maximum Entropy Method (MEM). Inclusion in matrix had the effect of slowing down the decay rate and extending the lifetime distribution over a larger time-interval with respect to solution. (C) 2010 Elsevier B.V. All rights reserved.