I have done multiple prints now using PVA glue mixed 1-2 with water on glass,( 2 water, 1 PVA) heated bed to 60c which also helps in keeping the bed amply warm and use a raft. Can’t believe how fantastic the prints are, no warping on 190 x 190 4mm print.
Clean the glass first and brush on the mix, heating the bed dries the PVA mix then print away, let the bed cool properly to remove the print and wash the glass under water to dissolve the PVA and start again.
Not tried hairspray but I heard this is also a good solution
Hope it helps