Bonding and molecular environment effects on photoorientation in epoxy-based polymers having azobenzene units
Ikusi/ Ireki
Data
2009-03Egilea
Fernández Salvador, Raquel
Mondragón Egaña, Iñaki Bixintxo
Galante, María J.
Oyanguren, Patricia
European Polymer Journal 45(3) : 788-794 (2009)
Laburpena
An azo prepolymer (TAZ) was synthesized by reaction between Disperse Orange 3 (DO3)
and diglycidyl ether of bisphenol A (DGEBA). The resulting TAZ was blended with DGEBA
and two different monoamines, one aliphatic and one aromatic, benzylamine (BA) and
m-toluidine (MT), to prepare various azo copolymers with different azo contents. In addition,
two guest–host systems were prepared: 5.16% by weight of DO3 in DGEBA-BA and in
DGEBA-MT polymers. Their reversible optical storage properties were studied and compared.
The maximum obtainable birefringence increases linearly with TAZ weight fraction,
independently of the power of the writing beam, the environment in which the azo moiety
is located, and the bonding between the dye and the matrix. It was found that, in BA-based
copolymers, with lower Tg, the fraction of birefringence conserved after relaxation is smaller
and the writing rates are higher than in MT-based copolymers. The film thickness dependence of the birefringence signal is also analyzed.