TABLE II: Fit parameters used in Eqs. (3a,b) for fits of Fig. 3. Vycor Gelsil5 Gelsil2.6 E (K) 1750 1750 1750 T$_{00}$ (K) 161 . 5 158 . 5 154 . 5 τ$_{0}$ (s) 10 − 13 10 − 13 10 − 13 γ 0 . 19 0 . 25 0 . 17 exponential β of the KWW-response function used e.g. in Eq. (8) of Ref. 45. Fig. 8 com- pares the temperature dependence of the dynamic correlation length ξ calculated from the two different methods and applying the hypothesized relation ξ = 2 (3 N$_{corr,}$$_{4}$V$_{salol}$/ 4 π ) 1 / $^{3}$, which results in excellent agreement. We used DSC values [33] of Δ C$_{p}$ ( d ) reported for salol confined in mesoporous silica in a wide range of pore sizes from 2.6 to 26.4 nm. The in- set of Fig. 8 shows that the dynamic correlation length at the glass transition temperature ξ ( T$_{g}$ ) for various pore sizes determined from Eq. (6) is rather constant with a mean value of about 3 nm. This overall behaviour of ξ ( T$_{g}$, d ) is very similar to calorimetrically determined characteristic lengths for salol in confined geometries [46]. Results of extensive dynamic mechanical measurements of the glass forming liquid salol confined in mesoporous silica with silanated pores are presented. It turns out, that silanation can completely remove the liquid-surface interactions. As a result the confinement induced acceleration of the dynamics can be measured purely, which leads now to a much stronger (as compared to uncoated pores) downshift of the glass transition temperature T$_{g}$ with decreasing pore size due to the hindering of cooperativity. Using the results of percolation theory [44] we have calculated the downshift of T$_{g}$ with decreasing pore size, which fits our data very well. In Ref. 44 it is also shown, that finite size effects are expected to set in when the pore size d ≈ 7 r$_{0}$ − 10 r$_{0}$ yielding 4 . 8 − 8 nm for salol with r$_{0}$ ≈ 0 . 8 nm. This is in very good agreement with our observations. 14 IV. CONCLUSIONS