SELF-ASSEMBLED ASYMMETRICALLY SUBSTITUTED POLYDIACETYLENE AS A NOVEL 2ND-ORDER NLO MATERIAL

Polymer chains of a novel asymmetric polydiacetylene, poly((8-butoxy c arbonyl)methyl urethanyl) 1-(5-pyrimidyl)-octa-1,3-diyne(BPOD) self as semble in an acentric stable polar organization upon spin coating. Spo ntaneous alignment of the urethane moiety caused by the intramolecular hydrogen bonds between the side groups appears to be responsible for this organization. An abrupt decrease of SH intensity at around 130 de grees C is found to be closely related to the breaking of noncentrosym mety in the films in conjunction with the disruption of these intramol ecular hydrogen bonds. Dielectric and infrared spectroscopy confirm th e relaxation of the stable hydrogen bonded polar organization at highe r temperatures.