Regensburg 2007 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 20: POSTER: Biological Systems + New Materials
CPP 20.30: Poster
Wednesday, March 28, 2007, 16:00–18:30, Poster B
Temperature-Dependent Holographic Studies of Azobenzene-Containing Diblock Copolymers — •Hubert Audorff1, Lothar Kador1, Carsten Frenz2, and Hans-Werner Schmidt2 — 1Universität Bayreuth, Physikalisches Institut und Bayreuther Institut für Makromolekülforschung (BIMF), 95440 Bayreuth — 2Universität Bayreuth, Makromolekulare Chemie I, 95440 Bayreuth
The light-induced reorientation of azobenzene and mesogenic side groups in the minority phase of diblock copolymers has been investigated with holographic methods at different temperatures. The materials consist of a matrix of polystyrene and minority phases which contain chromophores and mesogens in different ratios. Plane gratings were inscribed at temperatures between 20 ∘C and 90 ∘C. The influence of the temperature on the achievable refractive-index modulation, writing time, sensitivity, short-term relaxation, and long-term stability of the gratings was measured. With increasing temperature, the achievable refractive-index modulation becomes smaller, whereas the sensitivity is roughly constant. The stability drops strongly, when the glass transition temperature is approached.