Av. Metelitsa et al., PHOTOCHROMIC SPIROPYRANS OF COUMARIN SERIES, Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals, 246, 1994, pp. 37-40
Novel spiropyrans on the base of 4-methyl-7-hydroxy-8-formylcoumarine
(I) and 7-R-4-hydroxy-3-formylcoumarine (II) are synthesized. The comp
ounds (I) and (II) exhibit in solution respectively direct and inverse
photochromic reaction. The influence of the heterene moiety and solve
nt polarity on spectral and photochromic properties have been studied.
The indoline derivatives of (I) are also photochromic in crystal.