Well, it is almost like emmb says. After WWII in 1945 was all glass factories (only small glasshops as Skrdlovice had persisted private for a while)nationalised and Borocrystal n.p grounded, followed by Borské sklo and later Crystalex.
Trademark and label Borocrystal was used, however, also in 60ties and 70ties for pieces from Borske sklo n.p. and also for Borské sklo - Crystalex.
Paper labels at pictures focus me to 70ties. TK = technical control, ČSN = Czechoslovak national standard (at that time everything was standardised in technical norms)
Jindrich