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.
High Tg, Nonpoled Photorefractive Polymers / Li, H.; Termine, R.; Angiolini, L.; Giorgini, L; Mauriello, Francesco; Golemme, A. - In: CHEMISTRY OF MATERIALS. - ISSN 0897-4756. - 21:12(2009), pp. 2403-2409. [10.1021/cm8034664]
High Tg, Nonpoled Photorefractive Polymers
MAURIELLO, Francesco;
2009-01-01
Abstract
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
