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Synthèse et caractérisations d'une nouvelle famille de copolymères fluorés pour l'optique non linéaire quadratique

Abstract : Different types of fluorinated copolymers poly (arylène ether) were synthesized by polycondensation, the substitution of C-H groups by C-F groups leading to a decrease of the optical losses at 1.55 ¤m, which is interesting for the applications in the telecommunications domain. In order to accomplish this purpose, various types of chromophores, which contain tricyanovinyle groups as acceptor groups have been synthesized, and then they have been grafted on these polymers to have good properties in second order nonlinear optics NLO. Thermal analysis shows high thermal stability up to 350 °C and high glass transition temperature (Tg> 160 ° C). The refractive indices which were measured by ellipsometry were around 1.55. The second order susceptibility NLO coefficients (d33) determined by second harmonic generation (SHG) of the various films poled by electric field (Corona discharge) were found around 15 pm.V-1 at 1.907 ¤m, and the thermal stability of poled films has been observed up to 130 ° C. During the poling, a reversible fall of the SHG signal during the cooling has been observed around 120 °C. Various hypotheses have been studied to explain this fall. Finally the existence of a sub-glass transition in fluorinated copolymers was highlighted by dielectric analysis. Its origins seems strongly linked to inter-chains dipolar interactions
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https://tel.archives-ouvertes.fr/tel-00341976
Contributor : Ens Cachan Bibliothèque <>
Submitted on : Wednesday, November 26, 2008 - 2:46:55 PM
Last modification on : Thursday, July 2, 2020 - 5:16:03 PM
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Khaled Aljoumaa. Synthèse et caractérisations d'une nouvelle famille de copolymères fluorés pour l'optique non linéaire quadratique. Chimie. École normale supérieure de Cachan - ENS Cachan, 2008. Français. ⟨tel-00341976⟩

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