DIELECTRIC RELAXATIONS IN POLY(GAMMA-N-ALKYL L-GLUTAMATE)S .2. STUDY OF RELAXATION DUE TO MOTION OF THE SIDE-CHAIN AND THAT DUE TO MOTION OF THE MAIN CHAIN

In order to get detailed information about the beta -relaxation due to motion of side chains in poly( gamma -methyl L-glutamate), poly( gamma -ethyl L-glutamate) and poly( gamma -n-propyl L-glutamate), the frequency and temperature dependences of loss permittivity were determined in the frequency range from 10** minus **4 Hz to 10**5 Hz and at temperatures ranging from ca. minus 100 degree C to ca. 60 degree C. The shape of the loss permittivity as a function of frequency was independent of the side-chain length. The loci of loss-permittivity peaks on the relaxation map could be represented by two straight lines independent of the side-chain length. They intersect in the glass transition region associated with the alpha -relaxation due to the motion of the main chain. The activation energy below the glass transition region was thought to be essentially due to side-chain motion and estimated to be ca. 18 kcal mol** minus **1.