酸化鐵を含む硝子に就て (第6報)

抄録

The following are the studies made with an influence of sodium nitrate or potassium nitrate is added into a glass batch as an oxidizing agent.
(A) A study has been made as to respective colours of glasses and the state of oxidation of iron oxide in cases where sodium nitrate have been added increasing amounts there of from 0.5% to 6.0%, into respective batches of soda-lime-iron oxide silica glass in which the content of iron oxide being 2% and the content of soda being constant.
(1) It has been noted that the colour of the glass become slightly yellowish as the amount of sodium nitrate added is increased, and no change has been seen in the content of FeO in the glass, and in consequence there of the percentage ratio of FeO/FeO+Fe₂O₃ has been found constant.
(2) Next, the transmission curves has been studied of respective glasses by glass specimens having thickness of about 1mm. polished on both sides, and it has been founds that there is no difference in the form of curves and the limit of shortest wave length to be transmitted.
(3) When melted glass batches of same composition it has shown that the percentage ratio of FeO/FeO+Fe₂O₃ in a batch without being added with sodium nitrate is a little higher than that which being added with sodium nitrate, and the color of the former is relatively greenish.
(B) A study has been likewise made about glasses in which the alkali content is so kept as to be always 16% and one percent of wich come from sodium nitrate or potassium nitrate and also the lime content of the said glass composition being one by one replaced with ferric oxide, by using soda ash and chili nitre or potash and nitre as raw materials for alkali in such glass batches whose base glasses would be composed of 72% SiO₂, 12% CaO, and 16% Na₂O, 72% SiO₂, 12% CaO and 16% K₂O.
The following is the results:-
(1) The amounts of FeO and Fe₂O₃ contained in the glasses and the percentage ratio for FeO/FeO+Fe₂O₃ are as in the following table:
(2) As to the colour of the glasses, in case of of soda glass having a definite amount of chili nitre contained in batches it has been seen that yellowish green is dominating as iron oxide content increases. In case of potash glasses having a given amount of nitre in batches, greenish yellow colour has been strengthened as the iron oxide content increases. And in both glass series the colour have been found more yellowish and clearer than cases where batches have been melted without adding thereto any oxidizing agent.
(3) Compared the percentage ratio of FeO/FeO+Fe₂O₃ between the glasses melted by adding oxidizing agent and one melted by without adding the same agent. It has been found that the difhence is considerably small in case iron content is very small but the difference grows larger as the said content increases.
(4) Finally the transmission curves of such glasses have been determined. As comparing with those melted without adding into batches oxidizing agent the transmission are generally higher but there is found no diffreence between the said two glasses in the limit of wave lengthes which transmit.