Amorphous state of the ROR′-DADQs was prepared in two ways: (i) drop casting a ~ 3 µM solution of the compound in acetone on quartz (used f or recording the optical spectra of the amorphous f orm), and (ii) melt-quench of the powder sample placed between two cover slips (used f or monitoring the temporal evolution by X-ray dif f raction experiments and by f luorescence spectroscopy).