The terms "uniaxial" and "biaxial" come from the optical properties of materials in these states, which are the same as those of a uniaxial crystal or a biaxial crystal
. For T in the narrow range between T[S.sub.C] and [T.sub.SH], both the isotropic and the uniaxial phases are locally stable, and there is a first-order phase transition at the "nematic-isotropic transition temperature" [T.sub.NI], below which the ordered phase becomes the global minimizer.
[8.] Abdulhalim, I., "Exact 2 x 2 matrix method for the transmission and reflection at the interface between two arbitrarily oriented biaxial crystals
," Journal of Optics A: Pure and Applied Optics, Vol.