Accession Number:

ADA282271

Title:

Self Assembled Spin Coated and Bulk Films of a Novel Polydiacetylene as Second Order NLO Polymers

Descriptive Note:

Technical rept. 1 Jun 1993-31 May 1994

Corporate Author:

MASSACHUSETTS UNIV LOWELL DEPT OF CHEMISTRY

Report Date:

1994-05-31

Pagination or Media Count:

32.0

Abstract:

The polymer chains of a novel asymmetric polydiacetylene, namely poly8-butoxy carbonyl methyl urethanyl 1-5-pyrimidyl-octa-1,3-diyneD, in the absence of nonlinear optically active chromophores and without recourse to poling assemble in an acentric stable polar organization upon spin coating or solution casting. Asymmetry of the side groups and the spontaneous alignment of the urethane side groups by means of hydrogen bonds appear to be responsible for this organization. An abrupt decrease of SH intensity at around 130 deg C is found to be closely related to the breaking of noncentrosymmetry in the films in conjunction with the disruption of intramolecular hydrogen bonds. The changes observed were reversible below 130 deg C but becomes irreversible above this temperature. Comparison of absorption spectra of the polyBPOD films before and after thermal treatment indicate that only a slight change occurred in the absorption characteristics of the polymer backbone. FT-IR and dielectric spectroscopy confirm the relaxation of the stable hydrogen bonded polar organization at higher temperatures. Activation energies involved in this process were found to be a little higher than hydrogen bonding dissociation energies calculated from polyamide and polyurethane. The larger activation energies observed here indicate the combined effect of the hydrogen bonds followed by b relaxation. Symmetric polydiacetylene, Assemble in an acentric stable polar organization, Spontaneous alignment of the urethane side groups, Hydrogen bonds, Noncentrosymmetry, Intrammolecular hydrogen bonds.

Subject Categories:

  • Organic Chemistry
  • Polymer Chemistry
  • Coatings, Colorants and Finishes
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE