UV/vis spectra of the polymers obtained by the different reaction routes are shown in Fig. 2. Curve 4, measured from a saturated solution of P(I-co-II) in ethanol, represents an absorption spectrum with an intense transition centered at ∼209 nm, a band of lower intensity at 251 nm, and a broad band of low intensity with two maxima at 398 and 540 nm. Corresponding bands were observed
in the spectrum of a solution of P(I-co-II) in DMSO at ca. 261, 419,456, and 540 nm.