Way to glow

Do your dayglo T-shirts fade quickly in the wash? Matsui Shikiso Chemical
Company of Kyoto says it can make luminous pigments more waterproof, letting
them stay brighter for longer (GB 2 341 869). Calcium sulphide glows in the
dark, but only for a short time unless doped with radioactive chemicals. The new
idea is to dope strontium aluminate powder with a rare-earth metal, add
phosphoric acid and heat to 70 °C for four hours. The acid is then run off,
and replaced by sodium hydroxide for four hours. After drying, the powder has
“tremendously increased” water resistance, and is said to glow in the dark…