Manufacturers of optical coatings and components

Schott GG series glass acts as long pass filter, absorbing deep ultraviolet radiation and transmitting longer wavelengths.

With the exception of GG385 and GG395, GG series glasses are susceptible to staining and acid attack, but relatively impervious to alkali attack.  Schott GG385 and GG395 are ionically colored, whereas the rest of the GG series is colloidally colored.  In general, the colorants in colloidally colored glasses are highly dependent on secondary heat treatments during manufacture and exhibit variation within any given melt due to temperature gradients during the striking process.