Glass prepared from pyrogenically prepared silicon dioxide

1. A method of making glass comprising:

forming a dispersion of a pyrogenic silica with water, by mixing said pyrogenic silica with water,

gelling the dispersion,

drying the dispersion to obtain a microporous body,

sintering the body at a sufficient temperature for a sufficient time to produce a sintered glass body; and further comprising

adding acetic acid ethyl ester to the dispersion wherein the pyrogenic silica has the following physiochemical properties:

a) average particle size (D 50 value, D 50 ≧150 nm dynamic light scattering, 30 wt %);

b) viscosity (5 rpm, 30 wt %) η≦100 m·Pas;

c) thixotropy of T 1 : (η(5 rpm))/(η(50 rpm))≦2;

d) BET surface area 30-60 m 2 /g;

e) compacted bulk=100-160 g/L; and

f) original pH≦4.5.

2. The method according to claim 1 further comprising adding tetramethylammonium hydroxide to the silica and water to make the dispersion.

3. The method according to claim 1 further comprising pouring said dispersion into a mold.

4. The method according to claim 1 wherein the pyrogenic silica has a deacidification index of less than 3% on a weight basis.

5. A method of making a sintered glass comprising:

mixing a pyrogenically prepared silicon dioxide with water to form a homogeneous dispersion, said pyrogenically prepared silicon dioxide having the following physicochemical properties:

a) average particle size (D 50 value) D 50 ≧150 nm (dynamic light scattering, 30 wt %);

b) viscosity (5 rpm, 30 wt %) η≦100 m·Pas;

c) thixotropy of T i : (η(5 rpm)/(η50 rpm))≦2;

d) BET surface area 30-60 m 2 /g;

e) compacted bulk=100-160 g/L; and

f) original pH≦4.5; pouring the dispersion into a mold, gellng the dispersion in the mold to form a gelled body, removing the gelled body from the mold, and drying the gelled body to form a microporous green body, sintering the green body by zone sintering under vacuum to thereby obtain a sintered glass body.