From video description:
This is a demonstration of how I apply PVA glue to my glass print surface on my Reprap MendelMax 3D printer for printing with PLA filament. I can print PLA on bare glass for many objects, but for ones that are prone to lifting from the glass I use a coating of PVA glue which completely eliminates any first layer adhesion problems for me. I use a 1:10 dilute solution of PVA glue and water applied to the heated glass so the water evaporates quickly and I can control the thickness of the coating I apply. I can usually go for several prints without reapplying, depending on what I print. I usually set the bed temperature to between 50C and 60C for the entire PLA print and use fans on the nozzle and also across the build area.