Synthesis and photoluminescence stability of non-conjugated polymers based on fluorene and benzoxazole

A kind of non-conjugated blue luminescent polymer based on fluorene and benzoxazole was synthesized via solution condensation polymerization from 2,2-bis(3-amino-4-hydroxyphenyl)-propane and 2,7-dicarboxyl-9,9-dioctyl-fluorene and was characterized with H NMR, FT-IR, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), UV–vis absorption and photoluminescence (PL) spectroscopy. The polymer displayed the maximum photoluminescence emission peak at 415 nm and showed high PL spectroscopic stability. The green-to-blue emission intensity ratio IGreen/IBlue is only 0.073 even after thermal annealing at 150 °C for 30 h. After being exposed to UV light for 30 min, no bathochromic emission or obvious crosslink is observed. The common phenomenon of greenish blue emission of fluorene-based polymer around 525 nm has been effectively restrained in this polymer by introducing the isopropylidene group into the backbone of polymer.