FIELD: chemical industry. SUBSTANCE: described is lubricating composition for glass fiber. Lubricating composition is formed by solution having viscosity lower or equal to 400 comprising at least 5 wt.% of solvent and including at least one thermally polymerizable and/or cross linkable basis system. Said basis system comprises at least 60 wt.% of one or more constituents with molecular weight of lower than 750 and preferably lower than 500 containing at least one reactive epoxy function. Composition further comprises thermal initiator based on Lewis acid or base. Also described are glass fibers prepared by using said composition and coated with said composition. EFFECT: improved properties of the lubricating composition. 14 cl, 13 ex, 2 tbl
