I would try Googling glass blowing too.
It really does not "weld" per se.
We fuse it where I work though, but it is a glass/ceramic bond between an electrical insulator and a stainless tube. We just heat it to 2100F in a furnace. The stainless has to have some special chemical elements for the bond to work, and it is a very touchy process. You can find information on it by searching on glass fusing. The glass suppliers even run a week long school for process engineers to figure out how to do it.