Glass sodium oxide

Multicomponent Silicate Systems. Most commercial glasses fall into the category of sihcates containing modifiers and intermediates. Addition of a modifier such as sodium oxide, Na20, to the siUca network alters the stmcture by cleaving the Si—O—Si bonds to form Si—0-Na linkages (see Fig. 3c). 

Additionally, it is a source of sodium oxide and a fluidizing agent. The amount of sodium nitrate added in the glass manufacture process is up to 2 wt % of the total raw material. 

Fiber glass provides effective inhibition of polyethylene thermal destruction up to 400°C. The inhibitive efficiency increases with increased content of sodium oxide from 0.7-16% (Table 5). 

Adding sodium oxide to quartz glass breaks some of the Si—O covalent bonds left view, red outlines) to create terminal O ions associated with cations right view). This softens the glass, reducing its melting point. 

A desirable glass melts at a reasonable temperature, is easy to work with, and yet is chemically inert. Such a glass can be prepared by adding a third component that has bonding characteristics intermediate between those of purely ionic sodium oxide and those of purely covalent silicon dioxide. Several different components are used, depending on the properties desired in the glass. 

Addition of an alkali metal oxide as a "network modifier to the "network former causes pH sensitivity, i.e., small amounts of alkali metal induce superficial gel layer formation as a merely local chemical attack and so with limited alkali error larger amounts will result in more pronounced dissolving properties of the glass up to complete dissolution, e.g., water-glass with large amounts of sodium oxide. Simultaneous addition of an alkaline earth metal oxide, however, diminishes the dissolution rate. Substitution of lithium for sodium in pH-sensitive glass markedly reduces the alkali error. 

Soda (composed of sodium oxide) and potash (composed of potassium oxide) are relatively easy to obtain or to make, work, and handle. Although they do not occur naturally, they could be quite easily prepared in the past by burning some plants (see Textbox 28). Both these oxides were used as fluxes for making early types of glass articles, particularly small vessels and decorative objects. 

In contrast to the diversity in compositions encountered in the unrelated specimens above, all 45 samples of uncolored or amber glass with grisaille painting from the Chateau of Rouen were basically similar in composition. This glass contains about 15% potassium oxide and only about 3.5% sodium oxide (see Table II). Because these similar specimens came from the same building, a common source of manufacture seems likely. These data therefore support our belief that individual sources of glass produced compositionally consistent products. 

The set of samples from a panel at the Museum of Art, Princeton University (Figure 9) have internal compositional consistencies which allow conclusions similar to those for Rouen panels. Eleven fragments from this panel were sampled and analyzed (Table V). Potassium oxide concentration was about 26%, and sodium oxide concentration was about 0.5%. This glass is completely different in composition from that... 

Oxides of metals in Group 1 of the periodic table, such as potassium and sodium, are also highly reactive, though. It would not be safe to allow these chemicals to remain in the airbag, so the potassium and sodium oxides then react with silicon dioxide (Si02). This reaction forms an alkaline silicate powder. Alkaline silicate, a type of glass, will not burn and the resulting powder is harmless. 

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