Fig. 6

Alteration in alkaline environments. a Time evolution of the altered glass fraction calculated from the amounts of boron released into the solution for G0.40Nd4C glass under static conditions (T = 90 °C and S/V = 40 cm⁻¹). b Variation of the aluminum concentration. c Variation of the silicon concentration. d Evolution of the pH measured at 90 °C. At the end of tests at pH = 11.3 and 10.5, the glass is completely altered, although the retention of B (e.g., in calcium borates⁶⁴) explains AG_B% < 1