Photophysics of derivatives of trans-stilbenes in poly(vinyl alcohol) films

Absorption and fluorescence spectra of eight trans-stilbene derivatives have been measured in poly(vinyl alcohol) (PVA) films. Fluorescence quantum yields, φ_F, and mean fluorescence lifetimes, τ_F, have also been determined for these substances. Fluorescence quantum yields investigated in PVA films were found to be markedly higher than those measured in liquid solutions, this effect being even more pronounced with the mean fluorescence lifetimes. Radiative and radiationless deactivation constants k_F and k_d, respectively, were determined based on the measurements of φ_F and τ_F. The effect of donor-acceptor properties of substitutes δ_p upon the deactivation constants was examined. The energies of the 0-0 transitions between electronic states S₀ and S₁ were also affected by the donor-acceptor properties of the substituent, remaining in correlation with the Hammett constants δ_p.