Absorption in non-conjugated polymers

Due to the fact that electronic excitations also involve vibronic and rotational sublevels (the latter are not shown in Fig. 1.3), the absorption spectra of molecules consist of bands rather than single lines. It is notable that the maxima of the absorption spectra shown in Fig. 1.4 are located in the UV region. They reflect spin-state-conserving electronic transitions, i.e. transitions in the singlet manifold upon photon absorption, molecules in the singlet ground state So are 

Chart 1.1 Chemical structures of poly (vinyl acetate), PVAc poly (methyl methacrylate), PMMA polystyrene, PSt poly-(methyl vinyl ketone), PMVK poly(phenyl vinyl ketone), PPVK. 

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