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

The polarized Raman spectra of gamma-substituted propyl-triaikoxysilan es R1-(CH2)3-Si(OR2)3 [R1 = NCO (I), Cl (II), NH2 (III): R2 = C2H5; an d R1 = O-CH2-CH-CH2-O (IV); R2 = CH3) have been recorded, and an assig nment is proposed. The spectra are briefly discussed with emphasis on the glycidoxy compound (IV). Micro-Raman data are also given for the c o-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 c ondensation on some selected vibrational bands. No bands for residual, noncondensed Si-OH groups are found in the polymer spectrum from whic h 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 catalys t.