“…It follows from X-ray diffraction and polarised light scattering data that the polyimide gels contain both isotropic and anisotropic regions having approximately the same dimensions (~400-600 nm). 167 The second virial coefficients of solutions of the polyimide derived from anilinephthalein and bis(3,4-dicarboxyphenyl) ether in iV-methylpyrrolidone, dimethyl sulfoxide, chloroform, THF, and dimethylformamide have been determined.…”