Rather than seperation into positive and negative like you see in NaCl, SiO2 is a crystal rather than a molecule. It won't break into a positive and negative side in water like other dipoles.

So you'd see it either go left (which is to say form a crystal with the bond which doesnt happen due to hydrogen being more attracted to negative oxygen than o2 or Si) or go right (become surrounded by them) but remain as a whole particle. Particles that dont break their bonds just suspend in the solvent.