Photoinduced refractive index change of self-assembled spiroxazaine monolayer based on surface plasmon resonance

The self-assembly of a photochromic, spiroxazine-containing alkanethiol mon olayer on a gold surface is described. Contact angle measurements confirm t he presence of a hydrophilic surface in the self-assembled monolayer. Atomi c force microscopy (AFM) images and measurements confirm that this monolaye r was formed by stepwise chemical assembly. Evidence for self-assembled mon olayer-photochromism was gathered from UV-visible spectral evaluation befor e and after irradiation at 366 nm. Surface plasmon resonance (SPR) revealed that a resonance angle change of 0.13 degrees which corresponded to a refr active index change, Delta n, of 0.8034. (C) 2000 Published by Elsevier Sci ence Ltd. All rights reserved.