Light resistance. Polytetrahydrofuran ether glycol is a chemical substance with the molecular formula of HO [CH2 CH2 CH2 O] NH. A white waxy solid that becomes a transparent liquid when the temperature exceeds room temperature. Soluble in alcohol, ester, ketone, aromatic hydrocarbon and chlorinated hydrocarbon, insoluble in aliphatic hydrocarbon and water. When the molecular weight increases, the solubility will decrease. At room temperature, PTMEG has water absorption. Its water absorption depends on its molecular weight, and it can absorb up to 2% water. Dehydration and deoxidation are needed before use.