“Pebeo Vítrea 160 glass paints are excellent. One painted, you bake the item your oven (in accordance with the manufacturer's instructions) to 'fix' the paint.
Vítrea 160 does take a bit of getting used to, because it has a different texture from other types of paint, but with a bit of practice and patience the effects are magical.
I won't use anything else. Highly recommended”