In 1666 Sir Isaac Newton discovered that different colours of light had different indexes of refraction through glass. This meant he always assumed using glass lenses there would always be chromatic aberration as at the time the only glass available was soda lime. For this reason he designed the reflective telescope using mirrors to get around this idea.
At this time however people were starting to add lead to the soda lime glass process which enabled a change in refractive indexes and dispersion. This process led to the formation of the first flint glasses. Using the lead flint glass with the soda lime (crown) lenses chromatic aberration can be completely corrected. This discovery meant the first achromatic lens was manufactured by Chester Moore Hall in 1733. The first patent obtained for an achromatic lens was made by J Dolland in 1758.
In the 19th Century the focus of optical glass research then moved to Germany through the work of Joseph von Fraunhofer. Fraunhofer’s work helped to measure precisely the optical characteristics of glass through the Fraunhofer lines. These lines are nD (587.6nm) nF (486.1 nm) and nC 656.3 nm which ares till used today to characterise glass.
The next major step forward happened when Ernst Abbe who was working for Zeiss tasked Otto Schott with investigating the effects of different elements had on glass characteristics. This led to the discovery of several different glass categories that are still used today including borosilicate crown glasses, the barium crown glasses and the barium flint glasses. This discovery was really the starting point to todays modern optical glass production with companies in the UK, USA and Japan following suit.