New type of chiral photochromic liquid crystal polymers for colour photo-optical recording

Photo-optical properties of a cholesteric copolymer based on nematogenic an d photosensitive optical active lateral groups containing a benzeliden-p-me ntan-3-on fragment have been investigated. The selective light reflection w avelength was found to be controlled by the UV irradiation that causes the photoisomerization of the chiral photochromic groups. As a result the selec tive reflection of light can be changed locally. That permits the recording of a color image on a color background. The copolymer's photo-optical prop erties are compared with properties of a blend of cholesterol-containing co polymer with a low-molar-mass chiral dopant based on menthone derivatives.