The time profiles of fluorescence from a single vibrational level of SO(B(3)Sigma(-), v' = 3) were recorded at various He pressures. The radiative lifetime, 29 +/- 4 ns determined by a deconvolution analysis, is nearly identical with those of v' < 3. The rate coefficients for single-quantum relaxation, Delta v = 1, and multiquantum relaxation Delta v = 2 and 3, have been obtained from the He pressure dependence of dispersed fluorescence spectra. The Franck-Condon factors for v' = 3 -> v" = 0-23 in the B(3)Sigma(-)-X(3)Sigma(-) system have also been determined. (c) 2005 Elsevier B.V. All rights reserved.