Room-temperature photorefractivity without prepoling was demonstrated in polymers and copolymers with a glass transition temperature well above 100 degrees C. The compounds used are multifunctional side-chain polymers exhibiting chiral, semiconducting, photochromic, and nonlinear optical (azoaromatic moieties) properties. The photorefractive performance was linked to the reorientational effect of the photogenerated space-charge field, which well below the glass transition temperature can be active in the presence of the conformational mobility achieved via the trans-cis light-induced isomerization. The grating build-up time, which is long at lambda = 633 nm (with a time constant tau approximate to 500-1000 s) decreases by 2 orders of magnitude at lambda = 532 nm, where absorption is higher.
Titolo: | High Tg, Nonpoled Photorefractive Polymers |
Autori: | |
Data di pubblicazione: | 2009 |
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Handle: | http://hdl.handle.net/20.500.12318/6837 |
Appare nelle tipologie: | 1.1 Articolo in rivista |