Optical alignment of organic dopants in a solid gel matrix: dispersed and grafted rhodamine B molecules

Abstract

Abstract. We study herein the rotational mobility of organic dye molecules and their ability to align on a strong optical electric field when they are encaged in the pores of an inorganic silica xerogel matrix. We compare the case of dye molecules simply dispersed in the pores of the gel--and possibly held by hydrogen bonds--to the case of molecules chemically grafted on the inner surface of these pores through covalent bonds. The study is led on hybrid silicon-zirconium based inorganic matrices doped with organic rhodamine B molecules. The stronger holding of the dopants when these are grafted to the matrix enhances the molecular alignment--and thus the induced anisotropy--as well as the remanence of this alignment. Furthermore, we show that submitting the samples to a supplementary drying at higher temperature tends to increase both the alignment anisotropy and its stability. We explain these results in terms of mobility of the molecules, in relation to their immediate environment.

Optical Properties of Hybrid Organic‐Inorganic Materials and their Applications

“…[291] It was shown that the precuring and poling temperature impacts the nonlinear optical responses due to modification of the cross-linking. [155,156,292] An excessive cross-linking would decrease the mobility of the dyes and consequently lower the poling efficiency. This depends also in the rotational capacity of the dyes.…”

“…. ) via weak (Class I hybrid) [31] or strong (Class II hybrid) chemical interactions [151][152][153][154][155][156][157][158][159][160][161][162][163][164][165] is the main approach to achieve robust and functional photochromic-based devices that could be easily handled and integrated in solid materials. Many photochromic organic molecules have been entrapped in ORMOSIL (Organically Modified Silanes) hybrid matrices.…”

Synthesis of ORMOSIL silica/rhodamine 6G: Powders and compacts

“…Additionally, the preparation of hybrid fluorescent pigments using the sol-gel method was proposed by Hofacker and Schottner [12], enlarging the possible applications for this material. Few works using rhodamine in grafting reactions have been reported, where silica based monoliths and films were obtained [13,14].…”

Preparation and Properties of Siloxane/Epoxy Organic-Inorganic Hybrid Thin Films, Self-Standing Films, and Bulk Bodies

“…1 The organic/inorganic hybrids are classified based on their mixing and connections: 2 (1) dispersion type, (2) interpenetrating type, and (3) molecular hybrid type. In hybrids of (1) the dispersion type, inorganic materials are dispersed in organic polymers, [3][4][5] or organic materials are dispersed in inorganic polymers. 6 Because the organic and inorganic components in this type of hybrid are phase-separated, a homogeneous mixture of organic/inorganic hybrid materials is prepared by applying molecular interactions between organic and inorganic components such as hydrogen bonding and -interactions.…”