I suspect the answer to your question is that if you start with the amounts specified by the authors and then follow the protocol as described the gel that forms has that nominal composition, which the authors determined AFTER it formed.  So, I would say that the answer to your second question would be to scale any amount of NaOH they describe by the same factor as what you scale the rest of the solution by.  For example if they say they added 5 1mL aliquots of NaOH while working with 10g of solution, you would add 10 aliquots (or 5 2mL aliquots) to a 20g solution.  

Robert  E.Bachman

In my first question I mean that they say that make gel with first molar composition and after 7 days they add add a particular amount of 1 molar NaOH every 8 hr to first solution to have 0.43 Na2O in  final molar composition but the water molar composition didnt change in final composition.....

They didnt say how much use NaOH solution, They said that they add a particular amount of 1 molar NaOH to first solution to have 0.43 Na2O in molar composition, We just have the molar composition....

When you place 40 g. of NaOH in a 1-liter volumetric flask & add enough distilled water until you reach the mark on the flask’s neck, then you have prepared one-molar solution of NaOH. Assume that you added at intervals ¼ of this one liter volume, then the amount of NaOH that went in ,for gel formation, will be (1/4 X 40) = 10 grams. Of course, the water went inside but we cannot say that it is 250 mL because the total volume of the aqueous solution = volumes of solute & solvent so the volume of water is less than 250 mL. How much? We need to know the density of the solution that was prepared. But I think that NaOH plays the major role & water just accompanied it!