Li-6 alumino-silicate glass, a neutron shielding material, has been studied to determine if and to what extent it alters under natural conditions. Analyses included neutron depth profiling, prompt gamma activation analysis, x-ray diffraction, and scanning electron microscopy. Results indicate that the glass does undergo alteration, which results in Li-6 depletion within the first 10's of um of the glass's surface. Subsequent studies suggest that alteration is relatively quick, with the first 20 um of the surface altering after only 2 months of exposure to a natural environment. Although the extent of alteration is relatively small compared to the overall thickness of the shielding glass, thus not significantly effecting its shielding properties, the incorporation of H into the alteration layer may influence low H measurements by instruments lined with this glass.
and Turkoglu, D.
Natural Alteration of 6Li Neutron Shielding Glass, Physics and Chemistry of Glasses, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=925311
(Accessed December 10, 2023)