NOVEL CHOLESTERIC LIQUID CRYSTAL CONTAINING PHOTO-RESPONSIVE BUTADIENE CHROMOPHORE AND A PROCESS FOR THE PREPARATION THEREOF

摘要

The present invention relates to a color image recording medium and information recording process making use of novel thermo- and photo-responsive butadiene-linked cholesterols possessing chiral nematic liquid crystalline phases. The rewritable full colour image recording medium consisting of a pair of substrates at least one of which is transparent, containing an intermediate photo and thermoresponsive layer. The intermediate photo- and thermo-responsive layer consists of a butadiene linked cholesterol-liquid crystalline material. Rapid cooling of the cholesteric phase formed at high temperatures to ~0 °C results in formation of glasses in which the reflected colour characteristic of the film at the temperature from which it is cooled is retained. The colour of the glasses thus formed can be tuned by controlling the temperature of the film or irradiating it with UV light in the 350 nm region prior to formation of glass by rapid cooling. Using these processes the films can be tuned to any colour. These devices can therefore be used to record highly stable full color images by controlled heating or UV irradiation of the films. Images recorded by controlling the temperature can be erased by heating the sample, while images recorded using UV irradiation can be erased by irradiating with light in 266 nm region. The device is useful therefore for recording full colour images in a reversible manner.