We demonstrate the observation of quasi-periodic revivals out to 27 ps in an impulsively-aligned asymmetric-top molecule, sulfur dioxide (SO 2), at high sample temperature and density (295 K, 0.5 bar). We find that the asymmetric top exhibits a strong correlation between population alignment and population lifetime (r = 0.97), in accordance with the trend observed in linear molecules. We use a linear birefringence measurement fit to a full quantum simulation of the asymmetric rotor, and are able to separately measure both the population (T 1) and coherence (T 2) lifetimes of the rotational wavepacket. Additionally, we observe a high rate of elastic decoherence (T * 2 = 9.6 ps), and attribute this to long-range interactions mediated by the permanent dipole of the SO 2 molecule. We propose the use of birefringence measurements to study intermolecular interactions in a coherent ensemble, as a step toward using field-free alignment to investigate reaction dynamics and dissipative processes.