Novel Optical Functions of Compounds Derived from Cholesterol

A new cholesteric liquid crystals that respond quickly to stimuli such as temperature change or photoreaction of a doped compound in a liquid crystalline phase were found and stable molecular ordering below 80°C in the solid state brought about by rapid cooling from the liquid crystalline phase was noted. By changing the temperature at which rapid cooling start or degree of photoisomerization of photochromic compounds, colors from the visible spectral region reversibly fixed as interference colors. The compounds exhibited surface-directed self-assembly in a helical molecular ordering to form optically reflecting solid film on spin-coating from solution. All these may be considered properties of liquid crystals of medium-molecular-weight with over 1000 mass units. Through these properties, it is possible to obtain a re-writable full color recording in a photon or thermal mode.