Monitoring of the sol-gel synthesis of organic-inorganic hybrids by FTIR transmission, FTIR/ATR, NIR and Raman spectroscopy

The sol-gel synthesis of org.-inorg. hybrids based on triethoxysilaneterminated poly(ethylene oxide) and tetraethylorthosilicate was monitored in-situ using three spectroscopic methods (FTIR/ATR, Raman, NIR). These spectroscopic methods allow in-situ monitoring of the evolution of hybrid materials starting from the modification of the polymer and the early steps of hydrolysis up to the network formation. By application of 29Si solid-state NMR spectroscopy the assignment and quantification of the Raman bands to different end groups and different crosslinking states was made. The sol-gel reaction was also followed by in-line NIR spectroscopy. A multivariate data anal. was accomplished to obtain a conversion-time curve. Furthermore, we investigated spin-coated films on wafers using FTIR transmission spectroscopy.