Luminescence quenching method for probing the diffusivity of molecular oxygen in highly permeable media

The application of a recently developed phosphorescence quenching method in measurements of oxygen diffusivity (DO2) in polymeric media is reported. While we have determined accurate values of DO2, we can only report approximate values of permeability (PO2). The luminescence of two dyes in thin films of poly(n-butylaminothionylphosphazene) is measured. We find DO2 = (1.0 ± 0.2) × 10−5and (1.4 ± 0.4) × 10−5cm2s−1 for two dyes with different excited state lifetimes. Various reasons as to why the values of PO2 obtained from the two dyes differ by a factor of 3 are discussed.