The grain boundary groove shapes for equilibrated solid aminomethylpropanediol solution, BCC (AMPD-42.8 mol% NPG-3 mol% DC) in equilibrium with the liquid (AMPD-7 mol% NPG-3 mol% DC) have been directly observed by using a horizontal linear temperature gradient apparatus. From the observed grain boundary groove shapesrt (Γ), solid-liquid interfacial energy (σSL) of solid AMPD solution have been determined to be (5.20 ± 0.52) × 10-8 K m and (8.89 ± 1.33) × 10-3 J m-2, respectively. The grain boundary energy of solid AMPD solution has been determined to be (17.12 ± 2.73) × 10-3 J m-2 from the observed grain boundary groove shapes. The ratio of thermal conductivity of equilibrated liquid to thermal conductivity of solid AMPD solution has also been determined to be 0.35. © 2013 Elsevier B.V.