Steady-state, time-resolved fluorescence polarization behaviour and determination of dipole moments of coumarin laser dye

Steady-state and time-resolved fluorescence polarization studies have been carried out on coumarin 30 laser dye. The rotational reorientation of this probe has been measured in butanol at higher values of viscosity varying temperature. It is found that coumarin 30 rotates faster in butanol than in n-octanenitrile. The ground state (μg) and the excited state (μe) dipole moments are studied at room temperature in various solvents. These have been measured using absorption and fluorescence spectral band shift in solvent with varying dielectric constant (ε) and refractive index (n). It is observed that the dipole moment of excited state is higher than ground state dipole moment.