Whats the source and does that apply to when they started to supply Rolex?
The company split to create mb-microtec AG in 1968. Before then, the production of luminous colors were mainly supplied to Swiss watch making industries, and even to renowned scientists such as Marie Curie. The usage of tritium rather than glow paint was put into consideration for producing military-certified watches under the subsidy traser, and various other military components under glotac.
From their own web site
'In 1918 the company founders, Walter Merz and Albert Benteli, developed luminous substances for the watch industry. With a mixture of a synthetic resin and cellulose a new adhesive to fix the phosphorus on the dials was born'.
From 65 onwards they started to develope tritium gas for watches which lead to the formation of MB Microtec in 1968