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Proceedings Paper

Characterization of sol gel and ormosils via polarity-sensitive probes
Author(s): Aleksandra Lobnik; Otto S. Wolfbeis
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Paper Abstract

Conventional sol-gels are rather hydrophilic. A more hydrophobic material is obtained by preparing organically modified siloxanes (ormosils). We have used three different solvatochromic dyes, (1) ET-33, the best solvatochromic probe known so far, (2) Nile red (NR), and (3) a ketocyanine (KC) dye, all with unique solvatochromic properties in both absorption and fluorescence, to probe the micro-polarity of sol-gels. Because ET-33 has a very low molar absorbance and is not fluorescent at all, and KC was hardly soluble in the sol- gel solution, NR was preferably used. NR is an excellent probe and sensitive to the polarity of its microenvironment. Spectroscopic studies reveal remarkable changes in the absorption band positions as a function of the polarity of the sol-gel which depends on the different precursors used. Furthermore, aging time and temporal stability as a function of different ormosils have been investigated.

Paper Details

Date Published: 2 October 1997
PDF: 10 pages
Proc. SPIE 3136, Sol-Gel Optics IV, (2 October 1997); doi: 10.1117/12.284126
Show Author Affiliations
Aleksandra Lobnik, Karl-Franzens Univ. of Graz (Slovenia)
Otto S. Wolfbeis, Univ. of Regensburg (Germany)


Published in SPIE Proceedings Vol. 3136:
Sol-Gel Optics IV
Bruce S. Dunn; John D. Mackenzie; Edward J. A. Pope; Helmut K. Schmidt; Masayuki Yamane, Editor(s)

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