Correlation between structure, crystallization and thermally stimulated luminescence response of some borate glass and glass-ceramics

Structural analysis of oxyfluoride borate glass and BaF2 crystallization from phase separation

“…Meanwhile, Ba presents different coordination due to its sizes in aluminosilicate glass matrix. 13 Comparing the present results with our previous determination of apparent activation energy for barium and strontium diborate compositions, 39 we found that the incorporation of PbF 2 produces some modifications. Considering the energy of formation for O-M and F-M bonds (where M: Ba, Ca, Sr), 21 it is possible to conclude that during the formation of the glass phase, F-M bonds are preferred instead O-M, reducing the activation energy value.…”

“…Considering these models, the value for N 4 should be near 0.45 for the mentioned compositional range. Furthermore, if we consider previous reports on alkaline earth borates (for compositions of MO.2B 2 O 3 ), it was found that the structure of Ba glass consists of di‐pentaborate and di‐triborate groups with N 4 ~0.37, ~0.40, ~0.45, and 0.50 for the crystalline structure . From Molecular Dynamics calculations for Sr and Ca glasses, the structure was described as consisting of diborate groups with the same quantity of three and four coordinated boron, that is, N 4 ~0.5 .…”

“…18 Considering these models, the value for N 4 should be near 0.45 for the mentioned compositional range. Furthermore, if we consider previous reports on alkaline earth borates (for compositions of MO.2B 2 O 3 ), it was found that the structure of Ba glass consists of di-pentaborate [36,38,39] 1300-1450 H Nonbridging oxygen ions [35,36] Note: Where: H:High, M: Medium intensities.…”

“…From infrared measurement, and in accordance with neutron diffraction and RMN experiments, N 4 was estimated as ~0.4 and ~0.38 for Sr and Ca glasses, respectively . Our previous determination for Sr glasses indicates that N 4 was 0.37 . So, considering the experimental error, we can say that for the MO.2B 2 O 3 glasses, with M = Ca, Sr and Ba, N 4 should be between 0.4 and 0.5.…”

“…28 Our previous determination for Sr glasses indicates that N 4 was 0.37. 39 So, considering the experimental error, we can say that for the MO.2B 2 O 3 glasses, with M = Ca, Sr and Ba, N 4 should be between 0.4 and 0.5. Nevertheless, pursuing a correct interpretation of our Raman and FTIR results, we have to take into account that we have introduced a small amount of lead fluoride into the glass structure.…”