title: A sub-second, time-resolved, linear dichroism measurement system for visible attenuated total reflection spectroscopy with a slab optical waveguide.
abstract: A sub-second, time-resolved, linear dichroism (LD) measurement system was constructed, fitted with a slab optical waveguide (SOWG), and utilized to observe the adsorption process of methylene blue (MB) onto silica surfaces. In the system, a semiconductor laser (670nm) was used as the light source and the out-coupled beam from the SOWG was split by a polarizing beam splitter into two polarized beams (TE and TM modes) to allow sequential linear dichroic ratio data to be obtained; the acquisition rate was 11 data sets per second. For an MB solution that contained no sodium dodecylbenzenesulfonate (DBS), in contact with a bare silica surface, a clear decrease occurred in the average orientation angle of adsorbed MB in the initial stages of the adsorption process. This result may correspond to a change in the chemical form of MB from monomer to dimer.
authors.affiliation: Department of Chemistry, Faculty of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu 376-8515, Japan.
authors.forename: Kin-Ichi
authors.initials: K
authors.lastname: Tsunoda
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kasuya
authors.forename: Tomonari
authors.initials: T
authors.lastname: Umemura
authors.forename: Tamao
authors.initials: T
authors.lastname: Odake