Crystals of thermochromic spiropyrans containing mesogenic groups give isotropic melts. However, these materials form metastable films with mesogenic properties below the crystal melting points. A strong birefringence of the films appears concommitantly with the thermoconversion of-5% of the spiropyran into the colored merocyanine form. The mesophase is stabilized on alignment in an electrostatic field. Measurements of the optical ...
[Shvartsman, Felix P.; Cabrera, Ivan R.; Weis, Alexander L.; Wachtel, Ellen J.; Krongauz, Valeri A. Journal of Physical Chemistry, 1985 , vol. 89, # 18 p. 3941 - 3946]
