Light Scatterin Studies of Orientation Correlations in Cholesteryl Esters

Photographic and photometric light scattering patterns from the myristate, propionate and palmitate esters of cholesterol are analyzed in terms of theories previously developed for the scattering from crystalline polymers. The scattering is shown to result primarily from correlations in orientation of anisotropic elements. The solid state may exist in a negatively birefringent spherulitic form with a size dependent upon crystallization temperature, or may occur in the form of randomly correlated aggregates of crystals best characterized by a correlation function. Such random correlation persists through the smectice state. In the cholesteric state, there is a transition to disc-like non-random correlation with a correlation distance and non-randomness dependent upon the ester, temperature, and thermal history.