All-optical non-conjugated multi-functionalized photorefractive polymers via ring-opening metathesis polymerization

Non-conjugated multi-functionalized all-optical photorefractive (PR) polymers were designed and synthesized via ring-opening metathesis polymerization (ROMP) of two monomers using Grubbs II catalyst as an initiator. The polymers were characterized by infrared (IR) spectrum, gel permeation chromatography (GPC), UV-visible spectrum (UV-Vis), differential scanning calorimetry (DSC), thermogravimetry (TG) and so on. The number-average molar mass (Mn) of the polymers is no less than 8.5 × 104 while their glass transition temperatures of 52°C and 45°C are close to the room temperature, which is helpful to the enhancement of PR orientation and the fabrication of PR devices. The polymers have good thermal stability and great solubility in tetrahydrofuran (THF). Without any plasticizer, the transparent optical films can be prepared by solution-casting with THF solution of polymers. Their PR properties at 633 nm were evaluated by two beam coupling (TBC) experiments under zero electric field without prepoling. It is shown that the single-component polymer has obvious all-optical PR behavior.