Kerr Constant and Optical Anisotropy of Polymeric Chains

Theories of the Kerr constant Km and the optical anisotropy 〈(Δγ)2〉 of polymer molecules are developed on the basis of the additivity principle of bond polarizabilities and the rotational-isomeric-state approximation for rotations about skeletal bonds. Expressions are derived for both (i) polymer chains of finite length but of an arbitrary sequence of bonds and (ii) stereo-regular (or multirepeat) polymers of infinite length. The close similarity between Km and 〈(Δγ)2〉, and of them with the optical anisotropy ΔΓ of Kuhn's random link, is pointed out.