Mechanofluorochromism and thermofluorochromism of boron difluoride 3-methylamino-1,3-diphenyl-2-propen-1-one

Mechanofluorochromism and thermofluorochromism of boron difluoride 3-methylamino-1,3-diphenyl-2-propen-1-one have been detected. Upon grinding of crystals, they exhibit a significant change in their excitation spectra. A dependence of the luminescence spectrum on the wavelength of the exciting light has been found, which indicates the occurrence of luminescence centers of two different structures. Upon heating of a grinding sample, a further evolution of its luminescence and excitation spectra has been observed. The mechanism of the observed effects has been proposed to be associated with dissociation and formation of $J$-aggregates.