POLARIZED RAMAN-SPECTRA FROM SOME SOL-GEL PRECURSORS AND MICRO-RAMAN STUDY OF ONE SELECTED COPOLYMER

The polarized Raman spectra of gamma-substituted propyl-triaikoxysilanes R1-(CH2)3-Si(OR2)3 [R1 = NCO (I), Cl (II), NH2 (III): R2 = C2H5; and R1 = O-CH2-CH-CH2-O (IV); R2 = CH3) have been recorded, and an assignment is proposed. The spectra are briefly discussed with emphasis on the glycidoxy compound (IV). Micro-Raman data are also given for the co-condensation product of a 5:95 mixture of III and IV. The copolymer spectrum is compared to the precursor spectrum to show the effect of condensation on some selected vibrational bands. No bands for residual, noncondensed Si-OH groups are found in the polymer spectrum from which condensation to a three-dimensional network can be assumed to a high degree. The epoxy ring-breathing vibrational band indicates the ring to be cleaved only to a minor extent by reaction with the base catalyst.