In the work described in this paper the dielectric properties of solid
solutions of p-nitroaniline in poly(methyl methacrylate), poly(ethyl
methacrylate) and poly(n-butyl methacrylate) were measured in the freq
uency range from 20 to 10(6) Hz and the results obtained were compared
with those of the pure polymers. It is shown that the presence of the
solute has a strong influence on the relaxation process of poly(methy
l methacrylate), and this is ascribed to the formation of hydrogen bon
ds between the amino group of the solute and the side groups of the po
lymer. In poly(ethyl methacrylate) this effect is less pronounced and
it is absent in the case of poly(n-butyl methacrylate), suggesting tha
t the increasing size of the n-alkyl group prevents hydrogen bond form
ation between the solute and the polymer.