One-step synthesis of high Tg organo-soluble side-chain fluorinated polyimides containing a triazine-azo chromophore

A series of fluorinated copolyimides containing a triazine-azo chromophore were prepared by a one-step method. The copolyimides obtained were characterized by FTIR spectra, UV-Vis spectra, DSC, TGA and the prism coupling device. The copolyimides are soluble not only in aprotic organic solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethyl acetamide (DMAc), N, N-dimethyl formamide (DMF), dimethylsulfoxide (DMSO), but also in low boiling point solvents such as ethyleneglycol monomethyl ether and tetrahydrofuran(THF). They are almost completely transparent at wavelengths greater than 500 nm. All copolyimides possess high glass transition temperatures (T-g,T- 544-562 K) and are almost independent of the chromophore loading level. The 5% weight loss temperatures (T-5) of the copolyimides are more than 100 K higher than the corresponding T(g)s and this high thermal stability would ensure high-temperature electric poling of the copolyimides. The in-plane refractive index of a copolyimide is increased as the chromophore content is increased.