UV-induced blue thermoluminescence of annealed Na-rich aluminosilicates

• UV-induced blue TL of annealed albite is studied.
• Different annealing on several aliquots (from 480 to 960 °C) induces several changes in the TL sensitivity.
• Such changes are linked to dehydration, dehydroxylation processes and changes in the lattice structure.
• The Al/Si disorder gives rise to alkali self-diffusion and thermal stresses.

The luminescence properties of gemstones (silicates, carbonates, phosphates, etc.), are of interest since could be potentially employed as personal dosimeters not only in case of radiation accident or radiological terrorism where conventional monitoring was not established, but also as a UV personal dosimeter. We, herein, report on preliminary results of the UV-induced 480 nm-thermoluminescence (TL) response of a well-characterised natural albite (NaAlSi3O8) from Minas Gerais (Brazil) that, due to its high transparency, is used as gemstone. Different annealing on several aliquots (from 480 to 960 °C) induces several changes in the sensitivity of the sample probably associated with (i) dehydration and dehydroxylation processes and (ii) changes in the lattice structure increasing the Al/Si disorder giving rise to ionic self-diffusion of alkali atoms, thermal stress into atomic positions and variation in the concentration of alkali ions in planar defects. The complex structure of albite has several planar defects (twinning and exsolution interphases which contain hydroxyl groups, water molecules, etc.) that can act as luminescence centres. When the thermal preannealed samples are exposed to 1 h at 254.7 nm under lab conditions one can appreciate changes in the TL behaviour that allows us to think in the albite as a potential UV dosimeter. ©2006 Elsevier Ltd. All rights reserved.