Analysis of progression and LAM bands observed in infrared and Raman spectra of a series of vinylidene fluoride oligomers

Infrared and Raman spectra observed for a series of vinylidene fluoride oligomers with TGTG conformation have been analyzed focusing on the progression bands in the fingerprint region and the Raman bands of longitudinal acoustic mode in the low-frequency region. By the quantitative analysis of progression bands, the vibrational frequency-phase angle dispersion curves could be obtained on the basis of normal-coordinates treatment. From the analysis of longitudinal acoustic mode, the limiting Young's modulus of poly(vinylidene fluoride) crystal form II was evaluated to be 95.8 GPa. This value was found to be consistent with the modulus evaluated from the slope of acoustic branch of the above-mentioned dispersion curves.