A series of novel second-order nonlinear optical (NLO) polymers have been developed based on a precursor polymer prepared from the diglycidyl ether of Bisphenol A and aniline. The precursor polymer was postfunctionalized by azo coupling reaction and tricyanovinylation to form a number of NLO polymers with different conjugation lengths and electron acceptors. Post azo coupling reaction enabled the introduction of chromophores and extension of the conjugation lengths of the chromophores to take place in a single-step reaction. The chromophores introduced in the polymer system through covalent bonding not only define the NLO properties but also significantly modify other physical properties of the polymers. In this work, the correlation between chromophore structure and NLO polymer properties was extensively studied and the knowledge base was used to optimize polymer properties at the same time. The d33 value of 66 pm/V at 1.542 µm was determined for a representative polymer of the class containing tricyanovinyl azo chromophores. The NLO properties of these polymers exhibit long-term stability at 80 °C.
Two types of new nonlinear optical polymers have been synthesized
by postreaction of an
epoxy-based polymer prepared from the diglycidyl ether of bisphenol A
and aniline. The
new polymers DGEBA-AZO-TCV and DGEBA-AN-TCV were synthesized by azo
coupling
of the epoxy polymer with 4-(tricyanovinyl)aniline and by reacting the
epoxy polymer with
tetracyanoethylene, respectively. Using an azo coupling reaction
to functionalize the polymer
allows introduction of the tricyanovinyl (TCV) group and extension of
the conjugation length
to take place in a single-step reaction. In both synthetic routes,
TCV groups are introduced
at the last stage of the polymer preparation, thus preventing the
exposure of the TCV
chromophores to harsh reaction conditions. The
d
33 values for polymers
DGEBA-AN-TCV
and DGEBA-AZO-TCV were determined to be 27 and 66 pm/V at 1.542 μm,
respectively,
after corona poling. The two polymers retained 65% and 83% of
the initial d
33 values after
they had been heated at 80 °C for 1000 h.
ABSTRACT:A new organic/inorganic coating material based on the modification of a conventional melamine/polyol system has been developed. Polyhydroxyethylmethacrylate functionalized with alkoxysilane group was mixed with hexamethoxymethylmelamine. Upon heating under an acid catalyzed condition, both sol-gel reaction and melamine/polyol reactions occurred simultaneously, leading to highly crosslinked hybrid composites. The synthesis and characterization of the hybrid materials are reported. The organic/inorganic material was also coated and cured on polycarbonate substrates. The coated/cured samples exhibited excellent optical property. Surface scratch and abrasion resistance of the samples was found better than those of pristine polycarbonate substrate.
Polymeric materials with large nonlinear optical (NLO) coefficients are of interest for their potential use in electrooptic applications.1™3 The chromophores in the polymer matrix are oriented in a noncentrosymmetric fashion by poling for bulk second-order NLO properties.4™7 A major shortcoming of poled polymeric materials is the lack of long-term stability of the NLO properties. Promising schemes to overcome this problem include the incorporation of the aligned chromophores into crosslinked network structures or polymers with rigid backbones.7™11
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