Modeling Hydrogen Release From Doped Borosilicate Glass by Furnace or Lamp Heating

This paper explores the physical mechanisms responsible for so-called “photo-induced hydrogen outgassing”. The latter refers to enhanced hydrogen release rate from doped borosilicate glass samples during incandescent lamp heating compared with furnace heating. Experimentally, the glass sample was placed inside an evacuated silica tube. Both were modeled as plane parallel slabs exposed to diffuse furnace radiation or to collimated lamp radiation. Combined conduction, radiation, and mass transfer were accounted for by solving the one-dimensional transient mass and energy conservation equations along with the steady-state radiative transfer equation. All properties were found in the literature. The experimental observations can be qualitatively explained based on conventional thermally activated gas diffusion and by accounting for the participation of the silica tube to radiation transfer along with the spectral properties of the glass samples.