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A recent question mentions:

Bases are soapy to touch because of soap formation on contact with lipids present on our skin.

This is always the reasoning I hear, as well, and searching the internet gave the same results. However, when working with nitrile gloves, glass with aqueous sodium or potassium hydroxide on the outside always feels slippery. I believe that even nitrile-on-nitrile (rubbing the fingers together) gives the same slippery feeling. This effect is even stronger for the liquid in the base bath, but I assume that's because alkoxides would be detergents similarly to soap molecules in the absence of water.

Point is, if saponification is the culprit, why does the exterior of the glove experience a similar soapy effect to that my fingers feel? Could it be negative charges on the exterior of the glass? Is it possible for hydroxide to react with nitrile gloves to cause some similar kind of electrostatic repulsion, maybe by deprotonation or nucleophilic attack of the nitrile? This seems like a reasonable idea as far as glass goes, but I don't think that reasoning crosses over to gloves. Of course, I am not sure it really happens with glove-on-glove contact. I will safely test that theory again and edit if it's incorrect.

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    $\begingroup$ Hmmm... This PDF says that nitrile isn't a good glove for use with sodium hydroxide. This one, however, says the opposite. I was thinking, and I hope I don't havs to worry about this: $$\ce{OH^- + RCN -> ROH + CN^-}$$ $\endgroup$
    – SendersReagent
    Commented Mar 27, 2016 at 23:55
  • $\begingroup$ I know this is a little late, but couldnt it just be because liquids make things slippery? You can slide your hand/glove around a glass object easily when its covered by water/other non-oils. $\endgroup$
    – MadisonCooper
    Commented Mar 13, 2017 at 4:45
  • $\begingroup$ @ChildishJack It's true that liquids can make things more slippery, but there is a definite difference between glass with water on it and glass with aqueous hydroxide on it. The basic solution feels kind of oily on the surface (but rinses off with water), but plain water doesn't have the same level of effect. $\endgroup$
    – SendersReagent
    Commented Mar 13, 2017 at 7:18

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Glass itself is soluble in strong alkalis, forming sodium silicate solution, which is a syrupy, somewhat slippery-feeling substance. You can use sodium silicate to make a fire-resistant coating or high-temperature cement.

As you state, it's also possible the glove itself is being attacked. If the glass feels slippery in $\ce{NaOH}$ and $\ce{KOH}$ solutions, but not in $\ce{NH4OH}$, then it is most likely a silicate forming, though.

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