Photophysical properties, photostability and laser activity of 2,6-bis [β-(2-benzoxazolyl) vinyl] naphthalene (BBVN)

The photophysical properties such as electronic absorption, molar absorptivity, oscillator strength, transition dipole moment, fluorescence spectra and fluorescence quantum yield of BBVN were determined in different solvents and micelles. Both electronic absorption and emission spectra are slightly sensitive to medium polarity which indicates little change in the dipole moment of BBVN molecule upon excitation. The quantum yield for photochemical transformation (Фc) of BBVN was calculated in different organic solvents at room temperature. The dye solutions in DMSO, DMF, EtOH and CHCl3 give laser emission in the blue–green region upon excitation by a 337.1 nm nitrogen pulse, the tuning range, gain coefficient and emission cross-section have been determined. Excitation energy transfer from BBVN to rhodamine B was studied to improve the laser emission from this dye when excited by 337 nm. Such an energy transfer dye laser system (ETDL) obeys a long range culumbic energy transfer mechanism with a critical transfer distance, R0, of 42 Å and kET equal 1.6 × 1013 M−1 s−1.