The double exponential decay of the fluorescence anisotropy of tetracene on the 50 to 500 ps time scale is measured quantitatively using a photomultiplier having a risetime of 800 ps. Frequency-domain spectroscopy, that is, the measurement of the phases and amplitudes of the frequency components comprising the decay, is used. The experimental considerations for obtaining quantitative measurements are discussed. The results of the study suggest that tetracene does not behave according to the Debye-Stokes-Einstein model in the solvent 1-n-dodecanol.