MAC glue is the only glue that I would consider using for glass on glass mosaic art. It dries clear and quickly, and does not yellow like some other glues. It is terrific for glueing beads and other small tesserae. I have used it to make a "slurry" of beads, frit (crushed glass), glitter, colored sands to make sparkling mosaic features.
Years ago I discovered MacGlue for my glass-on-glass mosaic mandalas. I like the strong bond, quick drying time (20 to 25 minutes usually), and relatively clear result. “In the Beginning”, the first mosaic for which I used MacGlue, actually was part of the SAMA’s Mosaic Arts International in Miami some years back.