Electron spin relaxation of di-tertiary-butyl nitroxide in supercooled water

The linewidths and line shapes of electron spin resonance spectra of dilute solutions of di-t-butyl nitroxide in supercooled water were analyzed at temperatures ranging from 15 to −33 °C. The electron spin relaxation is mainly due to the motional effect of anisotropic magnetic interactions. The rapidly increasing linewidths at temperatures below 0 °C reflect a large temperature dependency of the viscosity of supercooled water.