Excellent quadratic non-linear optical (ONL-2) properties of the poly(2,5-bis(but-2-ynyloxy) benzoate, containing a polar diacetylene as a chromophore, were found. According with the Maker fringes method, oriented polymer films showing an order parameter of ∼0.23 can display outstanding and stable Second Harmonic Generation (SHG) effects under off-resonant conditions (SHG-532 nm). Also, the macroscopic non-linear optical (NLO)-coefficients were evaluated under the rod-like molecular approximation, obtaining: χ_zzz⁽²⁾ and χ_zxx⁽²⁾ in the order of 280 ± 10 and 100 ± 10 pm V⁻¹, respectively. The mechanical and chemical properties, in addition to the large ONL-2 coefficients exhibited by this polymer, make it a promising organic material in the development of optoelectronic/photonic devices.

A series of polymers containing diacetylene-containing polyethersulfone by oxidative coupling polymerization of dipropargyloxydiphenylsulfone (BPS) and dipropargyloxy bisphenol-A (BPA) monomers were synthesized; the reaction was carried out under mild conditions and afforded high yields. Using these copolymers, films were made to determine the permeability for the following gases: CO ₂ , CH ₄ , N ₂ , O ₂ . The copolymers were amorphous and soluble in organic solvents except that the homopolymer from bis(4-propargyloxy)diphenyl sulfone was a crystalline polymer insoluble in most organic solvents. Films of copolymers were cast from solutions of each copolymer in chloroform at room temperature. The amorphous copolymer films slowly underwent cross-linking reactions in solid state during storage given a stronger mechanical force to copolymer. The relationship between cross-linking and mechanical properties was also studied. The incorporation of the diacetylene groups in the chain backbone of copolymer caused less permeability with a factor of ten times in its comparison with the polysulfones based on bisphenol-A synthesized by nucleophilic condensation, on the other hand. Moreover, the combined ease of processing and resultant stability was highlighted.