Chain flexibility effect on the refractive index grating of fully functionalized carbazole/DO3/epoxy polymer

Chi Jung Chang, Wha Tzong Whang, Ken-Yuh Hsu

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2 Scopus citations


The photorefractive (PR), photoconductive, and holographic characteristics of 3-amino-9-ethyl carbazole (AEC)/dispersed orange 3 (DO3)/diepoxy main chain copolymers are investigated to study the relationship between the structure and properties. The recorded pattern exhibits good fringe contrast with the resolution 20 μm in the recorded hologram. The formation rate of refractive index grating (PR grating) can be speeded up by applying an electric field or changing comonomer structure or monomer composition. Faster PR response can be achieved by incorporating aliphatic diepoxy with longer chain length or increasing the concentration of the charge transport moieties, while more nonlinear optical (NLO) segment (DO3) in the copolymer results in higher diffraction efficiency. The dark decay rate of the PR film at room temperature depends on the dark conductivity and steric interaction between the NLO chromophores and the polymer matrix. However, the latter shows greater influence on the dark decay at elevated temperature. More charge transport segment increases the dark conductivity and it leads to higher dark decay rate. The diffracted signals of polymers synthesized from the diepoxy comonomers containing longer soft chain exhibit slower dark decay at room temperature, but drop sharply as the temperature get higher. In comparison with experimentally measured dark decay at elevated temperature, thermal stimulated current spectroscopy is a more sensitive tool than differential scanning calorimetry diagrams to evaluate what temperature a sharp dark decay of the PR signal will occur.

Original languageEnglish
Pages (from-to)1321-1333
Number of pages13
JournalJournal of Applied Polymer Science
Issue number6
StatePublished - 1 Dec 1999

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