烷氧基取代聚对苯乙炔三阶非线性光学性能

通过双醚化反应、氯甲基化反应以及在强碱性条件下进行的脱氯化氢反应制备聚（2-甲氧基-5-丁氧基）对苯乙炔（PMOBOPV）、聚（2-甲氧基-5-己氧基）对苯乙炔（PMOHOPV）、聚（2,5-二丁氧基）对苯乙炔（PDBOPV）和聚（2,5-二己氧基）对苯乙炔（PDHOPV）等四种可溶性聚对苯乙炔（PPV）衍生物，通过紫外-可见吸收光谱对产物分子结构进行表征.结果显示，PMOBOPV、PMOHOPV、PDBOPV和PDHOPV的共轭π电子发生π → π* 跃迁的吸收峰分别位于491 nm、495nm、504nm和510nm处，相应的光学禁带宽度分别为2.23eV、2.18eV、2.12eV和2.07eV.利用简并四波混频技术测量PPV衍生物的三阶非线性光学性能，探讨了分子结构对PPV衍生物三阶非线性极化率（χ(3)）的影响.研究发现，激发波长为532 nm时，PMOBOPV、PMOHOPV、PDBOPV和PDHOPV的共振χ(3)值分别为3.45×10－10、5.13×10－10、7.15×10－10和9.61×10－10 esu；激发波长为1064 nm时，它们的非共振χ(3)值分别为1.09×10－11、1.42×10－11、1.62×10－11和2.14×10－11 esu.

Third-order Optical Nonlinearities of Poly (p-phenylene vinylene) Derivatives with Alkoxyl Substituents

Poly (ρ-phenylene vinylene) (PPV) derivatives with symmetrical and asymmetrical alkoxyl substitutes including poly (2-methoxy-5-butoxy)-ρ-phenylene vinylene (PMOBOPV),poly (2-methoxy-5-hexyloxy)-ρ-phenylene vinylene (PMOHOPV),poly (2,5-dibutoxy)-ρ-phenylene vinylene (PDBOPV) and poly (2,5-dihexyloxy)-ρ-phenylene vinylene (PDHOPV) were prepared through bisetherification,chloromethylation and dehydrochlorination reaction and characterized by UV-Visible absorption spectrum. The results revealed that the conjugated absorption peak of PMOBOPV,PMOHOPV,PDBOPV and PDHOPV assigned to π→π* transition of π electrons were located at 491 nm,495 nm,504 nm and 510 nm and the optical bandgaps were also measured to be around 2.23 eV,2.18 eV,2.12 eV and 2.07 eV respectively. The third-order nonlinear optical susceptibilities (χ(3)) of PPV derivatives were studied by degenerate four-wave mixing technique and the effects of molecular structure on third-order optical nonlinearities of PPV derivatives were also investigated. The experimental results showed that the resonant χ(3) values at 532 nm of PMOBOPV,PMOHOPV,PDBOPV and PDHOPV were 3.45 × 10-10,5.13 × 10-10,7.15 × 10-10 and 9.61 × 10-10 esu,and the corresponding off-resonate χ(3) values at 1064 nm were 1.09 × 10-11,1.42 × 10-11,1.62 × 10-11 and 2.14 × 10-11 esu respectively.