Fast relaxation mode in a thermotropic uniaxial nematic liquid crystal

Results are reported from a light scattering measurement in the uniaxial nematic phase in the thermotropic liquid crystal octylcyanobiphenyl, a material which does not exhibit a biaxial phase. In addition to a slow Goldstone mode associated with twist fluctuations, a fast mode whose relaxation time is independent of both wave vector and temperature has been observed. The possible origins of this relaxation are discussed.