Photophysical properties and laser performance of ω,ω′-bis(oxazol-2-yl)-p-oligophenylenes

Abstract The photophysical properties such as singlet and triplet absorption, absolute fluorescence spectra, fluorescence quantum yields and fluorescence decay times as well as the laser performance (tuning range, conversion efficiency, photochemical stability) of 2,4,5-triphenyloxazole and four ω,ω′-bis(oxazol-2-yl)- p -oligophenylenes have been measured in dioxane at room temperature. With increasing number of phenyl rings between the terminally positioned oxazolyl groups the increasing fluorescence quantum yields and decreasing fluorescence decay times give rise to increasing conversion efficiencies. The conversion efficiencies of the ω,ω′-bis(oxazol-2-yl)- p -oligophenylenes are proportional to the calculated cross-section of the stimulated emission. The tuning ranges are in the violet—blue region between 409 and 438 nm. The photochemical stability under XeCl excimer laser pumping in dioxane ranges from 0.4 × 10 4 to 2.3 × 10 4 J l −1 . The effect of the oxazolyl group on the photochemical stability of laser dyes is discussed.