Two sapphire substrates are tightly bonded through a BaTiAl6O12-glass thin film, by irradiation with a
nanosecond laser. After the laser process, the composition of the glass sealant changes, due to in-
corporation of Al2O3 from the upper substrate. After annealing of the bonded samples (950 °C for
30 minutes) crystalline structures are observed by TEM which are attributed to crystalline BaTiAl6O12.
These crystals together with Al2O3:Ti centers are the responsible of the observ