Dielectric measurements have been made in thick films (∼100 μm) of polyvinyl butyral (PVB) having degree of polymerization n=1600, in the frequency range 100 Hz–100 KHz and temperature range 300–373 K. The results indicated that PVB was in the amorphous phase and observed dielectric dispersion has been assigned as the β-relaxation process. The β relaxation is of Debye type with symmetrical distribution of relaxation times. The dielectric relaxation strength Δε and the distribution parameters β̄ increase with temperature. The results can be qualitatively explained by assuming the hindered rotation of the side groups involving hydroxyl/acetate groups.

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Dielectric measurements have been made in the metastable solid phase of MBBA in the frequency range 1–100 kHz and in the temperature range −196 to 0°C. The results indicate a Debye-type dispersion with symmetric distribution of relaxation times. The dielectric relaxation strength (Δε=ε0−ε∞) varies with temperature and shows a maxima at about −60°C. The results can be qualitatively explained by assuming the free rotation of the dipoles in the temperature range above −60°C and a restricted rotation of the dipoles (or restricted number of active dipoles) in the low temperature region.

Dielectric measurements in the frequency range 0.7 to 3.0 MHz are made in the isotropic phase and in the nematic phase of OHMBBA magnetically aligned with the long molecular axis parallel to both the magnetic and rf electric fields. Measurements in the nematic phase indicate a Debyetype dispersion with a relaxation time of 7.4 × 10−8 s at 47 °C and an activation energy of 14 kcal/mol. The results can be explained by assuming the molecular rotation about a transverse axis occuring under hindering nematic potential. The dielectric permittivity (ϵ′⊥), measured with the magnetic field acting perpendicular to rf electric field, does not vary with the magnetic field intensity, which indicates that OHMBBA probably prefers homogeneous alignment with the electrodes.