NOVELTY - Coating glass onto a flexible stainless steel substrate involves: a) depositing a glass precursor directly onto at least a portion of a surface of a stainless steel substrate; and b) heating the glass precursor to form a glass layer on the surface of the metal substrate, where the glass layer comprises silicon dioxide, aluminium oxide, sodium oxide, boron oxide, and optionally an oxide selected from e.g. lithium oxide, beryllium oxide, barium oxide, magnesium oxide, potassium oxide, calcium oxide, manganese oxide, nickel oxide, iron oxide, and any oxide of a lanthanide metal.    USE - For coating glass onto a flexible stainless steel substrate (claimed), where the coated stainless steel substrate is used for manufacturing flexible solar cells (such as thin-film Cu(In,Ga)Se2 (CIGS) solar cells) and other articles in which a passivated stainless steel surface is desirable, where the articles is used as the substrate for the manufacture of electronic devices (such as organic light emitting diode display applications, white light organic light emitting diode applications, photovoltaic applications) and in medical devices such as heart valves.    ADVANTAGE - The process produces substrate that has flexibility of metal, surface properties of glass, and can be used in a roll-to-roll process for the manufacture of CIGS cells, without the need for interlayer coating between the glass coating and metal substrate. The process imparts glass-like properties to the surface of stainless steel substrate in order to overcome at least some disadvantages of using common glass substrates in e.g. photovoltaic cells. The glass layer can serve as a thermal and electrical insulating layer, or also as an ion barrier, preventing detrimental doping of CIGS from iron, chromium, vanadium, nickel, titanium, phosphorus, manganese, molybdenum, niobium (or columbium) upon thermal processing of solar cells at elevated temperatures (ion migration prevention at 600 degrees C has been indicated by electron spectroscopy for chemical analysis (ESCA)).    DETAILED DESCRIPTION - Coating glass onto a flexible stainless steel substrate involves: a) depositing a glass precursor directly onto at least a portion of a surface of a stainless steel substrate; and b) heating the glass precursor to form a glass layer on the surface of the metal substrate, where the glass layer comprises silicon dioxide (SiO2), aluminium oxide (Al2O3), sodium oxide (Na2O), boron oxide (B2O3), and optionally an oxide selected from lithium oxide (Li2O), beryllium oxide (BeO), barium oxide (BaO), magnesium oxide (MgO), potassium oxide (K2O), calcium oxide (CaO), manganese oxide (MnO), nickel oxide (NiO), strontium oxide (SrO), iron oxide (FeO), iron(III) oxide (Fe2O3), copper oxide (CuO), copper(I) oxide (Cu2O), cobalt oxide (CoO), zinc oxide (ZnO), lead oxide (PbO), GeO4, tin oxide (SnO2), antimony oxide (Sb2O3), bismuth(III) oxide (Bi2O3), and any oxide of a lanthanide metal.