The only "glass" on the moon I'm aware of and have read about is of meteorite impact melt origin, or possibly from ancient (or current?) volcanic activity involving rapid melting.
When a meteor strikes the lunar surface the energy is so great that it partially melts the immediate area around the impact spot. Sometimes the reflective glass particles are spread out from the impact zone in highly visible "rays", or "spokes".
"Clifford Simak set a novelette The Trouble with Tycho [bottom center], at the lunar crater. He also postulated that the crater's rays were composed of volcanic glass (tektites) akin to a theory postulated by NASA researchers Dean Chapman and John O'Keefe in the 1970s."