UNUSUAL CRYSTAL ORIENTATION AND ITS CONTROL IN 4-(N,N-DIMETHYLAMINO)-3-ACETAMIDONITROBENZENE (DAN) IN GLASS-CAPILLARY

We have studied organic crystal growth and its orientational control in glass capillaries using a modified Bridgman-Stockbarger method. In the course of this study, we obtained unusual crystal orientation in 4-(N,N-dimethylamino)-3-acetamidonitrobenzene (DAN) grown in a pre-baked capillary: the polarization axis (Z axis) is parallel to the capillary axis and is different from the reported orientation; i.e., 54 degrees with respect to the capillary axis. The control of crystal orientation in glass capillaries was successfully achieved in BAN-cored fiber prepared using pre-baked capillaries, though it was impossible in untreated capillaries. These facts suggest the importance of the interaction between the inner wall of a glass capillary and organic molecules in organic crystal orientation in glass capillaries.