Investigations on the organic crosslinking in ORMOCERs by means of Raman spectroscopy

FT-Raman spectroscopy was used together with supplementary C-13-NMR measurements to analyze the reaction of the epoxy moieties of 3-glycidoxypropyltrimethoxysilane and 5,6-epoxyhexyltrimethoxysilane during sol-gel processing. The corresponding reactions of the model compounds epoxypropane and epoxyhexane were analyzed to obtain the necessary Raman assignments of the resulting products. Based on these results the formation of the beta-hydroxy methyl ethers could be derived for the silanes. An additional polyaddition of the epoxy rings yielding a mixture of oligo ethers is also consistent with the Raman measurements.