Ok I did the titration and here are the results so far:
Adding phenolpthalein to the 5g Sodium silicate dissolved in water, it turned pink and was at a PH above 11
Using 0.5M HCl as the titrant and 5g sodium silicate dissolved, HCl added until pink disappeared and the PH strips measured below 6.8 (Strips range 0.3 increments;
Results after calculations: 0.93g Na2O this is 18.6% in this batch of powder
My other Sodium Silcate solution has 12% Na2O and 30% silicon dioxide at 1.5g per mL.
I will have to do the titration again tomorrow to be sure. I think I need to stop before the 6.8 is reached but also take a measurement both when the pink colour disappears and then when the PH is at 6.5. we will see what the results are then.