We have also analyzed our dynamic elastic data obtained for the different pore sizes in terms of a newly proposed theory [11] which relates the size of dynamically correlated regions to the temperature derivative of the dynamical two-point correlation function, which in our case can be identified with the dynamic susceptibility Y ( ω, T $_{)}$. The results clearly show an increase of the dynamic correlation length ξ with decreasing tempe- rature approaching ξ ( T$_{g}$ ) ≈ 3 . 2 nm. This value is very similar to the one obtained previously [4] from DSC and TMDSC data. For smaller pore sizes ξ ( T, d ) at a given temperature shifts to smaller values which is concomitant to the systematic decrease of the relaxation time τ ( T, d ) and the resulting downshift of T$_{g}$ ( d $_{)}$. However at the glass transition temperature the dynamic correlation length is almost independent of the pore size. Unfortunately at present there is no unique theory that relates the relevant parameters controlling the confinement effects in glass-forming materials to experimental data. The reason for this is that the microscopic mechanism behind the glass transition is still not completely understood and more theoretical (e.g. of the type presented in Ref. 47) and experimental work is required to close the gap of knowledge and understand confinement effects in glass-forming liquids. Acknowledgements : We thank Marie-Alexandra Neouze and the Institute of Materials Chemistry from the Vienna University of Technology for the N$_{2}$-characterization of our samples. We also thank Irena Dreven$_{ˇ}$sek-Olenik and Miha Devetak from the Jo$_{ˇ}$ zef-Stefan- Institute in Ljubljana for help concerning silanation, which was done within the ÖAD-WTZ project Sl 19/2009. Support by the Austrian FWF (P19284-N20) and by the University of Vienna within the IC Experimental Materials Science ("Bulk Nanostructured Materials") is gratefully acknowledged. 15 [4] E. Hempel, G. Hempel, A. Hensel, C. Schick, and E. Donth, J. Phys. Chem. B 104 , 2460 [3] G. Adam and J. H. Gibbs, J. Chem. Phys. 43 , 139 (1965). [2] M. D. Ediger, C. A. Angell and S. R. Nagel, J. Phys. Chem. 100 , 13200 (1996). [1] M. Cukiermann, J. W. Lane and D. R. Uhlmann, J. Chem. Phys. 59 , 3639 (1973).