Controlled synthesis of perfluoroaryl functionalized hybrid materials for optical applications based on NMR spectroscopy and molecular modeling
The synthesis of ORMOCER®*s (inorganic-organic polymers) for optical applications is studied in detail. Producing waveguide materials with the desired low optical losses at wavelengths of 1310 and 1550 nm requires a thorough control of the initial inorganic network formation, because absorption losses are particularly due to Si-OH bonds beside aliphatic C-H bonds. Therefore, the synthesis of UV- or thermally curable organopolysiloxane resins with minimized Si-OH content is crucial. The investigation of the sol-gel reaction of organoalkoxysilanes by 29Si-NMR spectroscopy provides a detailed insight into the influence of reaction conditions on the species and networks formed. Reaction parameters were optimized towards the formation of ORMOCER® resins suitable for waveguide applications. Finally, the material synthesis is completed by crosslinking organically polymerizable units present in the ORMOCER® resin to establish the inorganic-organic hybrid network. The experiment al work is accompanied by computational chemistry. Calculating electronic properties is of value in predicting silane reactivities as well as spectroscopic data of intermediates. Molecular modeling is a convenient tool for the visualization of structural details on the molecular level.