enchain vs unbind

enchain

verb
  • To restrain with, or as if with, chains. 

  • To link together. 

unbind

verb
  • To set free from a debt, contract or promise. 

  • To disable some kind of connection in software, such as a key binding. 

  • To take bindings off. 

How often have the words enchain and unbind occurred in a corpus of books? (source: Google Ngram Viewer )