AbstractThe rate of dissociation of a nonionic detergent, octylphenyl polyoxyethylene ether, was studied by a temperature‐jump technique. A relaxation process which is concentration‐dependent was observed. A linear relation between the reciprocal relaxation time and the detergent concentration above the critical micelle concentration was obtained, from which the rate constant of dissociationkn,n–1of one molecule of detergent from the micelle has been determined. Values ofkn,n–1equal to 0.4 ± 0.05 and 73 ± 5 sec−1at 24.8°C were obtained for detergents with 16 and 30 ethylene oxide units per molecule of surfactant, respectively, showing and increase of the rate constant of dissociation with the length of the hydrophili