Another mystery solved. IG glass, Ingridhütte, or Ingrid Glashütte, KURT WOKAN.
Not known when it was founded but it is mentioned in Euskirchen near Bonn, 1964. Big trouble with the unions after the Panorama program denounced him for underpaying his turkish workforce. The unions called him a cutthroat, he took the unions to court and lost the case in 1974.
Big trouble with American client Alladin International, sued them for payment of 23 million dollars for unpaid goods delivered - but he was only able to collect part of that. (1972)
Apparently Wokan at some time either moved the factory to Schneegattern, Austria, or operated one of the glassworks there in addition to the Euskirchen location.
(Schneegattern is where Riedel produce glass now)
The firm closed down in 1979
In the current Austrian Directory there is still a Kurt Wokan in Schneegattern, import, export and decoration of hollow glasswares. But there is no phone, no website - just a postal address. So we may assume Kurt (now 81) is no longer playing ball.