Many materials especially biological origin shows the transition only during heating like protein denaturation, starch gelatinization etc. But crystalline or semicrystalline polymeric materials exhibit glass transition which you can observe both during heating and cooling whereas melting is observed during heating and crystallization curve during cooling.
Prerna P. Dhawade٭ and Ramanand N. Jagtap "Characterization of the glass transition temperature of chitosan and its
oligomers by temperature modulated differential scanning calorimetry" Advances in Applied Science Research, 2012, 3 (3):1372-1382.
Galina G. Zhadan ~, Cesar Cobaleda, Ahmik L. Jones z, Fernando Leal, Enrique Villar
and Valery L. Shnyrov I "PROTEIN INVOLVEMENT IN THERMALLY INDUCED STRUCTURAL
TRANSITIONS OF PIG ERYTHROCYTE GHOSTS" BIOCHEMISTRY and MOLECULAR BIOLOGY INTERNATIONAL Vol. 42, No. 1, June 1997 Pages 11-20
Wajira S. Ratnayake, Chika Otani, David S. Jackson "DSC enthalpic transitions during starch gelatinization in excess water, dilute sodium chloride, and dilute sucrose solutions" University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln. 5-15-2012
You can search in google your specifics materials.