Relationship between Spectral Hole Burning and Stokes Shift of Organic Dyes in Polymer Systems

Several organic dyes were studied both by fluorescence spectroscopy and by persistent spectral hole burning spectroscopy. The chromophores realizing spectral hole formation at 20 K have small Stokes shift approximately less than 103 cm−1. It ascertains that the small Stokes shift related to the existence of appreciable zero-phonon line would be a requisite for the spectral hole formation of the chromophore. The realization of hole formation by using poly(vinyl alcohol) or photoreactive matrices for the chromophores which have appreciable zero-phonon line but don’t undergo light-induced chemical or conformational change is also discussed.