Condis Crystals of Small Molecules II. The Polymorphs of N, N'-bis(4- n -octyloxybenzal)-1,4-phenylenediamine (OOBPD)

The high temperature transitions between 300 and 500 K of N,N'-bis(4-n-octyloxybenzal)-1,4-phenylenediamine are analyzed by scanning calorimetry, optical microscopy, light transmission measurement, thermomechanical analysis and X-ray diffraction. The prior assignment of mesophase structure K3/385.2/K2/388.2/K1/415.3/H'/422.2/G'/426.9/I/436.6/C/475.4/N/505.4/Melt (temperatures in K) has been extended by the suggestion that K1 to K3 are conformationally disordered crystals.