No abstract

A series of diacetylenic monomers containing at least one aromatic substituent were synthesized.Since the aromatic side group is a rigid, pyrimidyl ring, it is necessary that the other side group has a high degree of flexibility to permit polymerization in the monomer single crystal. Among the five monomers synthesized, only 8-[ [(butoxycarbonyl)methyl] urethanyl] -1-(5-pyrimidyl)octa-1,3-diyne (BPOD) monomer crystals turned into a polymer upon 7-irradiation with 68% monomer-to-polymer conversion. Poly(BPOD) is metallic red as polymerized and highly soluble in chloroform and undergoes a dramatic color transition from red Umax = 510 nm) to purple (Xm" = 599 nm) upon the addition of a nonsolvent such as hexane. This red-to-purple transition going from good to poor solvent is interpreted as a single-chain phenomenon. Aggregation may follow as the rigid chains interact with each other and crystallize. This aggregation could be prevented by increasing the side group-nonsolvent interaction by employing a nonsolvent which has high polarity and hydrogen-bonding capability.

Abstract

A new cross-linked second-order nonlinear optical material based on an alkoxysilane dye and a multifunctional phenoxyl molecule has been investigated. The design approach to this polymer system is also discussed. The nonlinear optical chromophore can be directly bound to an aryl-bridged network during the curing process. After cross-linking at 200 °C for 30 min, the cross-linked polymeric material was found to be amorphous with a Tt of 110 °C and a degradation temperature of 278 °C. The poled and cross-linked sample exhibits a second-order nonlinear optical coefficient, d33, of 77 pm/V. After being subjected to thermal treatment at 105 °C for 24 h, a reduction of only 19% of d33 was observed for the poled and cured sample. This d33 value remained unchanged at 105 °C for another 144 h, to which measurements were carried out. Detailed characteristics of the cross-linked material are discussed.Recently, a cross-linked system based on an alkoxysilane dye and phenylsiloxane polymer was reported.9 Upon

We have successfully prepared the hetero-multilayered thin films composed of polydiacetylene microcrystals and gold and/or silver fine particles by means of electrostatic deposition technique, i.e., layer-by-layer deposition method, characterized the morphological structure of the thin films, and evaluated their optical properties.