Thermal Stability and Structural Characterization of Organic/Inorganic Hybrid Nonlinear Optical Material Containing a Two-Dimensional Chromophore

In this study, two nonlinear optic hybrid materials with different dimensional alkoxysilane dyes were prepared and characterized. One NLO silane (Cz2PhSO2OH- TES), a two-dimensional structure based on carbazole, had a larger rotational volume than the other (DR19-TES). Second harmonic (d33) analysis verified there is an optimum heating process for the best poling efficiency. The maximum d33 value of NLO hybrid film containing Cz2PhSO2OH was obtained for 10.7 pm/V after precuring at 150 °C for 3 h and poling at 210 °C for 60 min. The solid-state 29Si NMR spectrum shows that the main factor influencing poling efficiency and thermal stability was cross-linking degree of NLO silane, but not that of TMOS. In particular, the two-dimensional sol−gel system has a greater dynamic and temporary stability than the one-dimensional system due to Cz2PhSO2OH-TES requiring a larger volume to rotate in the hybrid matrix after cross-linking.