Chemical Durability of Glass Powders

To study their chemical durability in distilled water, the prepared glasses were ground using a ball mill (Pulverisette 6, Fritsch, France), then screened through two sieves with a different mesh of 0.1 and 1 mm size. Then, one gramme of glass powder was deposited in a flask containing 20 mL of distilled water. The initial pH of the solution is 6.5. A total of 10 samples for each composition were prepared and placed in a thermostatic bath at temperature = 25 ± 1 to follow the release rate for a varying time from 1 up to a maximum of 35 days.
The samples were taken out at different time points. The solution was then filtered, and its pH determined by a digital pH meter (Adwa-AD8000). An analytical balance sensitive (±0.1 mg) (Shimadzu AW220) was used to weigh the residual glass after drying it at 90 °C for 10 h.
The percentage of weight loss was obtained according to the following equation [18 (link)]: ${\mathrm{D}}_{\mathrm{R}}=\frac{{\mathrm{W}}_{\mathrm{i}}-{\mathrm{W}}_{\mathrm{t}}}{{\mathrm{W}}_{\mathrm{i}}}\times 100$
where W_i and W_t are the initial and final sample weights, respectively.