Irradiation, photochromic liquid crystalline compounds

The relation between the type of photochromic compound and its effectiveness to induce a phase transition is a point of interest. When unsubstituted azobenzene is added to 5CB, the phase transition is not induced even after prolonged irradiation. BMAB is by itself liquid crystalline whereas azobenzene is not. It seems to be essential for a triggering photochromic compound to have effective interactions with the host liquid crystal. 

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