Photochromism in furylfulgide single crystal under high pressures

nlc pressure effect on single crystals of photochromic furylfulgide, [2-[1- (2,5-dimethyl-3-furyl)-2-methylpropylidene]-3-isopropylidenesuccinic anhydr ide], has been investigated up to about 5 GPa through the measurement of ab sorption spectra at room temperature, The absorption edge of the opened-rin g (E-form) molecules in single crystal at about 2.6 eV shifts to lower ener gy with increasing pressure. The absorption band corresponding to the close d-ring (C-form) molecules is observed in the range of 2.0-2.6 eV and shows a red-shift with increasing pressure. The photo-induced reversible isomeriz ation was observed under high pressures, as is the same as under the atmosp heric pressure. pressure-induced transition to C-forn molecules was observe d when the pressures were over 2.5 GPa.