Synthesis and characterization of hindered polyphosphazenes via functionalized intermediates: Exploratory models for electro-optical materials

Several cosubstituent polyphosphazenes were synthesized that incorporate the nonlinear optical chromophore, disperse red 1 (DR-1), linked covalently to the polymer backbone through spacer groups. These polymers have a high chromophore loading (one DR-1 per repeat unit), have glass transition temperatures near 100°C, and are high refractive index materials (n = ∼1.71). The syntheses were achieved via unconventional reactions that involve functionalized poly(organophosphazenes). Disperse red-1 was linked to the polymers by two different methods that generate either an ester- or an ether-linked system. Techniques such as ¹H, ¹³C, and ³¹P NMR, gel permeation chromatography, differential scanning calorimetry, UV-vis spectroscopy, and optical birefringence were used to monitor the structures.