The orientation of DMF mols. in oriented polyacrylonitrile (I) [25014-41-9] films is related to an interaction of their CO groups with the polymer segments by a dipole assocn. The IR dichroism was examd. of I films, contg. DMF residue drawn to different extents. An introduction of Me acrylate mols. in I chains did not increase the no. of centers for polymer-solvent assocn. Numerical evaluation of the relative group orientation as a function of draw ratio suggested an alignment of solvent mols. corresponding to the segmental orientation of acrylonitrile and Me acrylate units in acrylonitrile-Me methacrylate copolymer [30396-85-1]. Acrylic acid-acrylonitrile copolymer [25214-69-1] had 2 types of polymer-DMF interaction: the assocn. of DMF mols. with acrylonitrile segments similar to those in the homopolymer, and addnl. interaction of DMF mols. with the CO2H groups by H-bonding which had no effect on the mol. orientation of the solvent or on film orientation.