Showing papers by "Zhen Li published in 1996"
TL;DR: In this paper, a ladder-like nonlinear optical polysilsesquioxane (NLO) polymer is used for in-situ poling and the dipolar orientation after poling is described by an order parameter Φ which was measured using an original linear optical technique.
Abstract: A new, specially designed nonlinear optical (NLO) polymer is composed of ladderlike polysilsesquioxane as a backbone and “side-on or end-on” fixed stilbene chromophores. In-situ poling was carried out simultaneously during film formation via solvent evaporation and crosslinking which was caused by sequential hydrolysis and condensation of remained Si-H groups on macromolecules. The dipolar orientation after poling is described by an order parameter Φ which was measured using an original linear optical technique–UV dichroism. Orientation order and its decay are influenced by chromophore loading, crosslinking degree and poling condition. Compared with corresponding single chain polymers, a poled thin film of ladderlike NLO polymers demonstrates more stable poling-induced orientation.
7 citations
TL;DR: In this article, the synthesis of spiro[4.4]nonane-1,6-diols via the catalytic as well as stoichiometric hydrogenation was studied, and the effects of the hydrogenation catalysts and reagents on the stereoselectivity of the products were observed.
Abstract: The synthesis of spiro[4.4]nonane-1,6-diols via the catalytic as well as stoichiometric hydrogenation of spiro[4.4]nonane-1,6-dione was studied. Profound effects of the hydrogenation catalysts and reagents on the stereoselectivity of the products were observed. The choice of solvent also was found to have a significant influence on the product selectivity. The opening of a spiro-ring in the starting material was identified as a major side reaction in alcohol solvents. The absolute configuration of the trans, trans-diol was unambiguously determined by X-ray crystallography.