LUMINESCENCE QUENCHING METHOD FOR PROBING THE DIFFUSIVITY OF MOLECULAR-OXYGEN IN HIGHLY PERMEABLE MEDIA

The application of a recently developed phosphorescence quenching meth od in measurements of oxygen diffusivity (D-O2) in polymeric media is reported. While we have determined accurate values of D-O2' We can onl y report approximate values of permeability (P-O2). The luminescence o f two dyes in thin films of poly(n-butylaminothionylphospazene) is mea sured. We find D-O2 = (1.0 +/- 0.2) x 10(-5) and (1.4 +/- 0.4) x 10(-5 ) cm(2) s(-1) for two dyes with different excited state lifetimes. Var ious reasons as to why the values of P-O2 obtained from the two dyes d iffer by a factor of 3 are discussed.