Fig. 2. Synthesis and characterization of main-chain spiropyran-based polymers. Top: synthesis via head-to-tail ADMET polymerization and 1H NMR sectional spectra (600 MHz, 32 scans, CDCl3) of monomers and polymers: (A1) MSP1 and PSP1, (B1) MSP2 and PSP2, (C1) MSP3 and PSP3, (D1) MSP4 and PSP4. Full 1D and 2D NMR spectra are provided in the ESI, Section 9.† The assignment of the proton resonances was assisted through the analysis of 1D and 2D NMR spectra of precursors and desired products as described in ESI, Section 9.† Details of the polymerization conditions can be found in the ESI, Section 2.† Bottom: dimethylacetamide (DMAc)-size exclusion chromatography (SEC) traces of PSP1 (A2), PSP2 (B2), PSP3 (C2) and PSP4 (D2).
