Low-temperature heat capacity of two polymorphs of glycine (α and γ) was measured from 5.5 to 304 K and thermodynamic functions
were calculated. Difference in heat capacity between polymorphs ranges from +26% at 10 K to -3% at 300 K. The difference indicates
the contribution into the heat capacity of piezoelectric γ polymorph, probably connected with phase transition and ferroelectricity.
Thermodynamic evaluations show that at ambient conditions γ polymorph is stable and α polymorph is metastable.