Physica B 350 (2004) e1115–e1118 Dynamics of confined glass-forming systems observed by neutron scattering Reiner Zorn a, *, Bernhard Frick b , Lutz Hartmann c , Friedrich Kremer c , Andreas Sch . onhals d , Dieter Richter a a IFF, Forschungszentrum J . ulich, D-52425 J . ulich, Germany b Institut Laue Langevin, F-38042 Grenoble, France c Universit . at Leipzig, D-04103 Leipzig, Germany d Bundesanstalt f . ur Materialforschung und -pr . ufung, D-12205 Berlin, Germany Abstract In this article, results on the microscopic dynamics of a low-molecular glass former and a polymer confined in nanoporous silica obtained by inelastic neutron scattering are presented. By combining time-of-flight spectroscopy and backscattering spectroscopy we are able to cover a large dynamical range, from the low-frequency vibrations to the a relaxation. The most prominent effect was observed on the ‘‘boson peak’’ in the vibrational spectrum. A strong reduction of the modes at lowest frequencies could be observed in both cases. The main effect on the a relaxation is a broadening for the salol system. For the polymeric system a difference of the confinement influence on the methyl-group rotation and the a relaxation can be detected from a first qualitative interpretation of the data. r 2004 Elsevier B.V. All rights reserved. PACS: 64.70.Pf; 61.41.+e; 61.20.Lc Keywords: Glass transition; Confinement 1. Introduction The dynamics of liquids and polymers confined in mesoscopically small (1–10 nm) pores, tubes or lamellae has become a field of increasing interest in experimental physics. The main reason for these studies are recent theories which explain the rapid increase of the viscosity in liquids when approach- ing the glass transition by a diverging ‘‘coopera- tivity length’’ [1]. Inelastic/quasielastic neutron scattering is a valuable technique to investigate such systems, because it is directly sensitive to the molecular motion and by suitable choice of isotopes the confined liquid can be selectively observed. 2. Experimental technique In order to cover a large dynamical range neutron time-of-flight spectroscopy and backscat- tering spectroscopy (IN6 and IN16 at ILL, ARTICLE IN PRESS *Corresponding author. Fax: +49-2461-615757. E-mail address: r.zorn@fz-juelich.de (R. Zorn). 0921-4526/$-see front matter r 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.physb.2004.03.303