Thus, the XRD data agree well with the UV data in that the
flattened fiber samples contain three modifications whereas in the
films of Set 3 only two of them are present. With progressive
decrease in the overall degree of ordering, all weaker reflections
(including the small-angle superstructure ones) disappear first,
leaving the three most intense lines. Then only one reflection at
9.50 deg. (d ¼ 9.30 Å) survives. A similar phenomenon, viz. preservation
of the position of the strongest diffraction maximum aftera phase transition, has been reported earlier for some polydialkylsilanes