ABSTRACT
We report the first use, over an extended temperature range, of dynamic light scattering in the presence of electric fields as a means of determining the elastic and viscotic constants of a nematic liquid crystal. We have studied 4-cyano-4′-pentyl-biphenyl (5CB) over its entire nematic range and give values of the twist elastic constant (k22) and the twist viscosity (γ1) as a function of temperature. The data are compared with existing literature values and we conclude that the method is accurate and reliable.