Re: what is the product of borax and polyvinyl alcohol called?

White glue, like Elmer's, contains several ingredients, but they are all polyvinyl alcohol (PVA) based glues. Since slime can be made with straight PVA (see this previous answer), I'll limit the discussion to that. PVA is a polymer composed of a long hydrocarbon chain with hydroxyl (-OH) groups attached to every other carbon:

-[CH2-CH-CH2-CH-CH2-CH-CH2-CH]n-
      |      |      |      |
      OH     OH     OH     OH

When PVA is in aqueous solution (actually a colliodal suspension), the hydroxyl groups become ready acceptors for hydrogen bonding, which increases its interaction with the water molecules, making it soluble as compared to polyvinyl. This hydrogen bonding also allows the PVA molecules to interact slightly with each other, such that at higher concentrations, a PVA solution becomes slightly viscous. During plasticization of PVA, the hydroxyl groups are covalently crosslinked to create a solid mesh of connected chains. However, as you know from your experiments, slime remains fluid, so this covalent crosslinking is not occuring. What is happening is that borate, B(OH)₄^-, can form strong hydrogen bonds with all four of its hydroxyl groups, and so the borate forms hydrogen-bonded crosslinks between the PVA molecules (see diagram below). While these hydrogen bonds are relatively strong, they are also quite dynamic, such that they are constantly forming and dissociating with the crosslinks moving randomly among the PVA molecules. The result is that over short intervals, the strength of the crosslinks gives the slime its elasticity, but over longer periods, the dynamic nature of the crosslinks allows the PVA molecules to move relative to each other allowing the slime to ooze. Because all of the interactions are non-covalent, there is no actual chemical reaction between the PVA and the borate, so there is no "product of borax and polyvinyl alcohol" formed. About the only name I could think of is simply the descriptive, "aqueous polyvinyl alcohol colloid with borate crosslinking."

reference