How can I make an alloy wetter?
The surface of glass has many Si-O-H and Si-O-Si bonds; deeper inside would be Na and Ca and Al. An active metal might engage those surface atoms. Na might be too reactive (forming a dross of NaOH on the surface of your alloy, or reacting with water at the glass surface). Aluminum or zinc or perhaps magnesium might be active enough to contribute some sort of adhesion to glass. 

Tin oxide is bound to glass surfaces for electrical conductivity. Perhaps it could be an intermediate layer, bonding glass and your alloy. And silver is deposited on glass to make mirrors. Your alloy might well stick to a silver deposit. So, while this doesn't actually make your alloy wetter, it could solve your problem of adhering to glass.