would you expect a noncrystalline material to have grain boundaries?

Question

material science

Answer 1

In materials science, the term grain has a meaning specific to crystal structures, so the answer would have to be no.

In a more general sense, the granularity of any material is the atom or molecule. Below that level, you are no longer talking about smaller pieces of the same material, but instead are talking about more fundamental components of atoms (electrons, nucleons (protons/neutrons (quarks))).

Answer 2

yes of course, though maybe not "grain" boundaries. Think of a material which sphericle grains, for example maybe a polymeric substance.