TABLE I: N$_{2}$ adsorption characteristics and elastic moduli of untreated and silanated porous silica samples. moduli of both natural and silanated mesoporous samples at room temperature. Orthogonal parallelepipeds of about 2.9 x 3.0 x 3.1 mm 3 were used to gather resonance spectra from 50 to 1100 kHz. For each sample 25 peaks resulting from excited resonant eigenmodes and corresponding overtones then were fitted via a Lagrangian minimization routine gaining bulk modulus K and shear modulus G (see Tab. I) with an accuracy of less than 1%. For further experimental details see e. g. Ref. 39. Young´s modulus Y was calculated from Y = 9 KG/ (3 K + G ) and used to calibrate DMA raw data at room temperature (see Figs. 1, 2 and 3). 6 Gelsil 2.6 Gelsil 5 Vycor untreated av. pore diameter (nm) 2.6 5.0 7.5 surface area (m $^{2}$/g) 590 510 70 pore volume (cm $^{3}$/g) 0.38 0.68 0.21 porosity φ 0.36 0.54 0.40 bulk mod. K (GPa) 9.6 3.9 8.1 shear mod. G (GPa) 7.7 3.3 6.7 Young´s mod. Y (GPa) 18.2 7.7 15.8 silanated av. pore diameter (nm) 2.4 4.8 7.5 surface area (m $^{2}$/g) 260 325 65 pore volume (cm $^{3}$/g) 0.15 0.4 0.19 porosity φ 0.30 0.49 0.33 bulk mod. K (GPa) 9.6 3.3 9.1 shear mod. G (GPa) 9.0 3.9 9.0 Young´s mod. Y (GPa) 20.6 8.9 20.3