Fourier-transformed near-infrared luminescence studies of the O-2((1) Delta(g)) --> O-2((3) Sigma(g)(-)) transition in H2O in the presence of various concentrations of the singlet oxygen quencher sodium azide were performed. In neat H2O (tau similar to 4 mu s) the signal-to-noise (S/N) ratio obtained was 236. In the presence of 10(-2) M NaN3, where the Lifetime of O-2((1) Delta(g)) is reduced to approximately 180 ns, the O-2((1) Delta(g)) phosphorescence could still be detected with an acceptable S/N ratio of 8. From these measurements a bimolecular rate constant of (5.8 +/- 1.1) x 10(8) M(-1) s(-1) for NaN3 was obtained.