THERMOCHROMISM OF SPECIFIC CRYSTAL FORM OXOTITANIUM PHTHALOCYANINES STUDIED BY ELECTROABSORPTION AND X-RAY-DIFFRACTION MEASUREMENTS

Thermochromism was found in phase II and Y-form oxotitanium phthalocya nines (TiOPcs) from the observed temperature dependence of the absorpt ion and X-ray diffraction spectra of various crystal forms of TiOPcs. Thermochromism has not been observed in amorphous and phase I TiOPcs. The temperature dependence of the electroabsorption spectra of phase I I was also different from that of phase I. This distinctive behavior w as discussed in terms of the crystalline packing structure of each TiO Pc.