Unraveling the Mystery of Roman Flexible Glass or Unbreakable Glass (Vitrum Flexile): A Chemical Perspective

Abstract

The first known description in history for the invention of flexible glass or unbreakable glass (vitrum flexile) was during the reign of the Roman Emperor Tiberius Caesar (from 14 A.D. to 37 A.D.). Saint Isidore of Seville recounted the stories by Petronius (ca. 27 A.D.–66 A.D) and Pliny the Elder (23 A.D.–79 A.D) of an unknown inventor who brought to Tiberius Caesar a drinking bowl made of a flexible glass (Vitrum flexile) material. Caesar threw the flexible glass (vitrum flexile) bowl to the floor and the glass bowl was dented but not shattered or broken. For over 1500 years, this story recounted by Saint Isidore of Seville has been considered a myth since no flexible glass artifact has ever been discovered.
In this article, it will be demonstrated that the invention of flexible glass or unbreakable glass (vitrum flexile) during Roman times was possible and feasible with the technology that was available to the Romans. The chemistry used by the Romans to produce this material will also be discussed. It was feasible that boron trioxide (borax) was available to the ancient world and to the Romans. Since, borax contains both boron and sodium (Na2B4O7∙10H2O) it is proposed here, that the ancient Roman inventor could have produced a earlier type of Borosilicate glass where after heating (SiO2 with borax) at extreme temperatures over 1,600°C or 2,912°F, a combined borosilicate glass of SiO2. B2O3.Na2O could have been obtained. The resultant compound produced (SiO2. B2O3.Na2O ) would have similar properties to modern day Borosilicates and be considered an unbreakable or shatter‐proof glass.