Radiative transitions between the three lowest-lying electronic states of molecular oxygen have long provided a model to study how collision-dependent perturbations influence forbidden processes. In an isolated oxygen molecule, transitions between the O-2(X-3 Sigma(-)(g)), O-2(a(1)Delta(g), and O-2(b(1)Sigma(+)(g)) states are forbidden as electric-dipole processes. For oxygen dissolved in organic solvents, the probabilities of radiative transitions between these states increase appreciably. Attempts to interpret solvent-dependent changes in the radiative rate constants have principally relied on O-2(b(1)Sigma(+)(g)) and O-2(a(1)Delta(g)) emission experiments. However, the dominant nonradiative deactivation channels of O-2(b(1)Sigma(+)(g)) make it difficult to quantify solvent effects on the O-2(b(1)Sigma(+)(g)) -> O-2(a(1)Delta(g)) radiative process. Thus, an appreciable amount of important information has heretofore not been available. In the present study, we examined the effect of 17 common organic solvents on the O-2(a(1)Delta(g)) -> O-2(b(1)Sigma(+)(g)) absorption transition at similar to 5200 cm(-1) (i.e., similar to 1925 nm). The solvent-dependent absorption coefficients at the band maximum, em, range from 5 to 50 M-1 cm(-1) and correlate reasonably well with the solvent refractive index; emax is largest in solvents with the largest refractive index. This observation is consistent with a model in which oxygen is perturbed to a greater extent by solvents with a large electronic polarizability. Through the Strickler-Berg equation, we also used these absorption data to obtain the radiative rate constant for the O-2(b(1)Sigma(+)(g)) -> O-2(a(1)Delta(g)) transition, and the results are consistent with a model in which the O-2(a(1)Delta(g)) -> O-2(X-3 Sigma(-)(g)) transition is said to steal intensity from the O-2(b(1)Sigma(+)(g)) -> O-2(a(1)Delta(g)) transition.