Cold process to make glass
Not glass per se, but silica is often produced chemically by silicon alkoxide gelation to create aerogels.

The problem with creating glass by some cold process would be that the reaction side-products, such as water, would have to be removed, leaving holes in a froth of glass. This is fine for creating an aerogel, but is not helpful in making solid objects, such as test tubes or lenses. Of course, you could sinter the glass frit or froth, but that still requires heating.