What kind of glass is this ?

[cb9420]

are these made from boro bars glow, origins glow frit or what ?
they look clear when they are not in the dark ?

[p.j.]

looks like frit

[Dave Umbs]

My guess would be GL 33 glow glass since they make glow frit. Eu glass sells it; im not 100% sure though if this is the case.