C03B 32/00

Thermal after-treatment of glass products not provided for in groups {[CPC: C03B19/00]} , [CPC: C03B25/00] - [CPC: C03B31/00] {or [CPC: C03B37/00]}, e.g. crystallisation, eliminating gas inclusions or other impurities; {Hot-pressing vitrified, non-porous, shaped glass products}