Dielectric absorption measurements are made on three ethylene‐carbon monoxide copolymers containing 2.3, 8.7, and 18 CO per 1000 CH2 at frequencies ranging from 1 kHz to 1 MHz throughout the 90–373°K temperature range. Mean values of the activation energies of the γ, β, and α relaxations are found to be, respectively, 11.5, 41.5, and 31 kcal/mole from measurements done at fixed frequency by varying the temperature and 27 kcal/mole for the α relaxation as obtained from measurements at steady temperatures with drifting frequencies. The interaction energy of the CH2 unit in the crystalline polyethylene chain with its neighbors is calculated on the basis of the chain rotation model as well as of the rotation‐translation model proposed by Hoffman et al. It seems that their αc models accounting for the molecular origin of the α relaxation have to be rejected. It is further shown that the sharp decrease of permittivity for high temperature (above 330°K at 1 kHz) is only due to the marked decrease of the density of polyethylene with increasing temperature.

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