摘要
本文分别在TE和TM模式下通过衰减全反射法(ATR)测定质量分数为0～22.8%对硝基偶氮苯侧链的含氟聚酰亚胺的热光系数dn/dT和热膨胀系数β值。结果发现,dn/dT和β、热光系数的偏振依赖性d△n/dT与面内外热膨胀系数差△β都随偶氮苯侧链含量的增加而同步线性增大,表明热膨胀行为是决定侧链型含氟聚酰亚胺热光性能的关键因素,折射率和极化率的影响则相对较小。
Attenuated total reflection （ATR） configuration is used for thermo-optic coefficients （dn/dT） and coefficients of thermal expansion （β） investigation of fluorine-containing polyimides with azo side-chain concentration of 0～22wt% in TE-and TM-polarized lights,respectively.Results indicate that the values of dn/dT andβincrease linearly with the azo side-chain concentration.Moreover,the polarization dependence of thermo-optic coefficients （d△n/dT） and the difference of coefficients of thermal expansion （△β） increase linearly with the azo side-chain concentration as well.The behavior of thermal expansion is a more important factor to determine the thermo-optic properties than refractive and polarizability for polyimides.
关键词
非线性光学
热光系数
热膨胀系数
衰减全反射
含氟聚酰亚胺
nonlinear optic
thermo-optic coefficient
coefficient of thermal expansion
attenuated total reflection （ATR）
fluorine-containing polyimide
