A chiral and thermally irreversible photochromic fulgide derivative incorporating an (R)‐binaphthol unit in its acid anhydride moiety was used for the photoswitching of the pitch length of cholesteric liquid crystals. Since the absorption maximum wavelengths of both thermally stable photoisomers are nearly in the UV region (quasi‐stealth photochromism), it can be exposed to visible light without inducing photochromic reactions. Therefore, when the photoswitching molecule is added to a permanent cholesteric liquid crystal whose reflection light wavelength is in the visible region, the UV light‐induced photochromic reaction of the photoswitching molecule changes the wavelength of the reflection light in the visible light region. We have succeeded in regulating the color of cholesteric liquid crystalline cells between red and blue upon UV light irradiation. Attempts to introduce this system in polymer dispersed cholesteric liquid crystals are also described.

中文翻译：

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手性，热不可逆和准隐身的光致变色掺杂剂，可控制胆甾型液晶的选择性反射波长。

掺有（R）-酸酐部分中的联萘酚单元用于胆甾型液晶的节距长度的光开关。由于两种热稳定的光异构体的最大吸收波长几乎都在紫外线区域（准隐身光致变色），因此可以将其暴露于可见光而不会引起光致变色反应。因此，当将光开关分子添加到反射光波长在可见光区域的永久胆甾型液晶中时，光开关分子的紫外线诱导的光致变色反应会改变可见光区域的反射光的波长。我们已经成功地在紫外线照射下将胆甾型液晶单元的颜色调节为红色和蓝色之间。