Polymeric materials are of great value as they are widely used in everyday society, making it important to synthesize and characterize these materials to enhance them. Galactomannan (Gal), for example, is a neutral natural polymer isolated from the legume endosperm and has substantial use in biomedical, food, cosmetic, and pharmaceutical industries. This research objective was to evaluate the influence of the addition of glycerin on Gal's thermal properties. The material was prepared using heating solutions of pure Gal containing the following glycerin contents: 0.5 and 1.0 mL. Characterizations were performed using Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Thermal analysis shows that Gal does not have glycerin in its composition and vitrifies rapidly with the rise of temperature, a process not observed in Gal containing glycerin. Therefore, Gal without the addition of plasticizer presents better characteristics to be applied as glue.