We have measured the temperature T dependence of the proton Zeeman relaxation rate R in polycrystalline 1,3-di-t-butylbenzene (1, adopt two two-correlation-time models using Bloembergen-Purcell-Pound spectral densities; one based on the dynamical inequivalence of the methyl groups in each t-butyl group and one based on the dynamical inequivalence of different t-butyl groups, either because of intramolecular effects or because of intermolecular (crystal-structure) effects. In the low-temperature phase of 1,3-DTB, R (e, P is unusual in that it is Larmor-frequency dependent in the short-correlation-time limit (i.e. , temperatures above the relaxation rate maximum). We have fit the data with a Havriliak-Negami spectral density (which reduces to a Davidson-Cole spectral density when one of the parameters becomes unity which, in turn, reduces to a Bloembergen-Purcell-Pound spectral density when an additional parameter becomes unity). The fit, with an effective activation energy of 10+3 kJ/mol, suggests that this low-temperature phase in 1,3-DTB is a glassy state. We relate the Havriliak-Negami spectral density to the Dissado-Hill spectral density which has a fundamental microscopic basis and which has been used to interpret a vast quantity of dielectric relaxation data as well as some mechanical relaxation data.