I hope you read the entire message , this is the easiest glass lens making technology . There are some books on sol gel silica glass at google books free.
I am talking about making a gel from some chemicals , dry it at microwave oven at 80 celcius not 800 and than cook the part at a oven at 200 celcius not 2000 and creating your own glass.
This is lowest heat needed glass making technology.
This is sol gel silica glass making method and not a very old technology. There is a 35 dollars scientific paper at google research and it is from British professor Ed Sym and he is talking about shoup method and very low temperature glass making technology for glass sculpturers.
There is many Florida University patents on creating low temperature aspherical extremelly precise and cheap lenses. This technology company is geltec or geltech and their products are cheap and very high precision that laser quantum experiments grade.
They are making polycarbonate 2.5 times bigger cnc machined molds , fill the mold with this chemical gel than after this net shape operation dry and cook at very low temperature this material. It shrinks 2.5 times and make the lens.
Now lets talk about practical advantages , if you want to create your cnc machined lens mold , it gives the mold tooling marks and your gel copy these marks on itself. But shrinking deletes these marks and exchange with nonreflecting fractal patterned surface.

Best ,

Mustafa Umut Sarac