Glycerin can be found in chemists and cosmetic stores, it is well known for its moisturising properties and is found in many hair products. I would recommend combining roughly 30% Glycerin and 70% water in a spray bottle and using it on the hair and scalp to benefit from it's moisturing properties.
Glycerin is a humectant which means it uses moisture from the air. When it is sprayed onto hair it gets absorbed by your strands which moisturises, softens and slows down loss of moisture which is highly beneficial for your hair. You can also use Glycerin on a dry scalp.