The alkali metal ions are small and mobile; their presence in glass allows a degree of electrical conductivity, especially in molten state or at high temperature. Their mobility decreases the chemical resistance of the glass, allowing leaching by water and facilitating corrosion. Alkaline earth ions, with their two positive charges and requirement for two non-bridging oxygen ions to compensate for their charge, are much less mobile themselves and also hinder diffusion of other ions, especially the alkalis. The most common commercial glasses contain both alkali and alkaline earth ions (usually sodium and calcium), for easier processing and satisfying corrosion resistance. Corrosion resistance of glass can be achieved by dealkalization, removal of the alkali ions from the glass surface by reaction with e.g. sulfur or fluorine compounds. Presence of alkaline metal ions has also detrimental effect to the loss tangent of the glass, and to its electrical resistance; glasses for electronics (sealing, vacuum tubes, lamps...) have to take this in account.
What component gives glass the ability to conduct electricity?
alkali metal ions

In 1579 a number of the northern provinces of the Low Countries signed the Union of Utrecht, in which they promised to support each other in their defence against the Spanish army. This was followed in 1581 by the Act of Abjuration, the declaration of independence of the provinces from Philip II.
What was the purpose of the Union of Utrecht?
to support each other in their defence against the Spanish army

The Yiddish linguist Max Weinreich published the expression, A shprakh iz a dialekt mit an armey un flot (" ": "A language is a dialect with an army and navy") in YIVO Bleter 25.1, 1945, p. 13. The significance of the political factors in any attempt at answering the question "what is a language?" is great enough to cast doubt on whether any strictly linguistic definition, without a socio-cultural approach, is possible. This is illustrated by the frequency with which the army-navy aphorism is cited.
What does "A shprakh iz a dialekt mit an armey un flot" mean in English?
A language is a dialect with an army and navy