We have measured the Raman spectra of ethylene‐vinyl alcohol copolymer (EVOH) and poly(vinyl alcohol) (PVOH). Spectra of 88% hydrolyzed PVOH were examined from the partially crystalline solid, from PVOH dissolved in both H2O and D2O, and from films precipitated from these solutions. The spectrum in H2O differs from that of the starting material by disappearance of sharp bands having Raman shift values of 1146 and 1093 cm−1, strengthening of a band near 915 cm−1, decrease in frequency of bands at 480, 1356, and 1441 cm−1, and increase in frequency of bands at 369, 413, 1023, 1371, and 2910 cm−1. The spectrum of the film shows partial reversal of these trends. With D2O as the solvent, the band shifts are slightly different from those listed above and new bands appear. These changes are indicative of loss of crystallinity, change in stereochemistry, and partial deuteration of hydroxyl during dissolution of this PVOH sample at room temperature. © 1994 John Wiley & Sons, Inc.

19F magnetic shielding anisotropies of the fluoromethanes have been obtained from studies in a smectic liquid crystal solution using a pulsed FT NMR spectrometer. The value of Δσ obtained for methyl fluoride in the smectic phase is observed to be comparable in magnitude but higher in accuracy than the previous measurements obtained from theoretical, clathrate, molecular beam, and nematic single phase techniques, with the earlier value obtained using the nematic–isotropic two-phase method being obviously in error. The shielding anisotropy measured for fluoroform is found to agree with the prior nematic two-phase value, with the nematic single-phase and clathrate values being considerably lower. The anisotropy measured in this investigation for methylene fluoride was found to be in disagreement with both previous values measured via molecular beam and nematic two-phase techniques. It is shown that on transforming the experimental shielding anisotropy values obtained in this study along the C–F bond direction, that σ11, the shielding component parallel to the C–F bond ,is essentially constant in magnitude for all three systems. In addition, it is also observed that from a knowledge of the signs of the orientation parameters that the absolute signs of the indirect proton–fluorine nuclear spin–spin coupling constants for the fluoromethanes are found to be unambiguously positive.

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