EMISSION CHARACTERISTICS AND PHOTOSTABILITY OF 1,4-BIS[BETA-(2-BENZOXAZOLYL)VINYL]BENZENE (BBVB) LASER-DYE

The fluorescence efficiencies (Phi(f)) of 1,4-bis[beta-(2-benzoxazolyl)vinyl]benzene (BBVB) have been measured in various hydrogen bonding and non-hydrogen bonding solvents of different polarities on the pi* scale. In hydrogen bonding solvents Phi(f) increases with increasing pi* value. The fluorescence has also been studied in other media, including micellar, microemulsion and acidic ones. BBVB solutions exhibit short excited state lifetimes in the range 0.5-0.7 ns. The second-order rate constant of oxygen and rhodamine 6G (R6G) quenching of BBVB fluorescence have been determined from Stern-Volmer relations. The critical transfer distances for the BBVB/R6G system have been determined as R(0) = 46.8 and 48.5 Angstrom in ethanol and methanol respectively. The photochemical quantum yields (Phi(c)) have also been determined in various organic solvents.