The 91st Annual Meeting of the German Society of Glass Technology (DGG) takes place from May 29 – 31, 2017 in the city of Weimar, Germany. 139 oral and poster contributions cover a wide scope of topics reaching from the fundamentals of the glassy state and amorphous materials to energy applications of glass topics related to health, medical, and biological applications as well as optical materials and devices, and finally to glass production technology.

Weimar is a city in the German federal state of Thuringia. It is located between Erfurt in the west and Jena in the east, approximately 80 km southwest of Leipzig. Together with the neighbouringcities Erfurt and Jena, it forms the central metropolitan area of Thuringia with approximately 500,000 inhabitants, whereas the city itself counts a population of 65,000. Weimar is well known because of its large cultural heritage and its importance in German history.

The city was a focal point of the period of Enlightenment in Germany and home of the leading characters of the literary genre of Weimar Classicism, Johann Wolfgang von Goethe and Friedrich Schiller. Before this, the great composer Johann Sebastian Bach had dwelled in the city (1708-1717). In the 19th century, famous composers like Franz Liszt made a music centre of Weimar and later, artists and architects like Henry van de Velde, Wassily Kandinsky, Paul Klee, Lyonel Feininger and Walter Gropius came to the city and founded the Bauhaus movement, the most important German design school of the inter-war period. However, the political history of 20thcentury Weimar was inconsistent: It was the place where Germany's first democratic constitution was signed after the 1stWorld War, giving its name to the Weimar Republic period in German politics (1918–33). Sadly, the city was mythologized by the Nazi propaganda; the nearby location of the concen­tration camp Buchenwald is a witness of this dark period.

Until 1948, Weimar was the capital of Thuringia. Today, many places in the city centre have been designated as UNESCO World Heritage sites (either as part of the Weimar Classicism complex or as part of the Bauhaus complex) and tourism is one of the leading economic sectors of Weimar. Relevant institutions in Weimar are the Bauhaus University, the Liszt School of Music, the Duchess Anna Amalia Library and two leading courts of Thuringia (Supreme Administrative Court and Constitutional Court). In 1999, Weimar was the European Capital of Culture.

At the Opening Ceremony of the congress, the Otto Schott Memorial Medal will be bestowed to Prof. Christian Rüssel, Friedrich Schiller University of Jena. During the ceremony, he will give a keynote lecture “News from glass crystallization“.

Finally, the organizers want to express sincere gratitude to the manifold contributors to this event, and to the numerous sponsors. Special thanks go to the symposia chairs who did their very best in composing and organizing the symposia programmes.

Prof. Dr. Reinhard Conradt President of the Deutsche Glastechnische Gesellschaft (DGG)

Dr. Ulrich Roger Managing Director of the Deutsche Glastechnische Gesellschaft (DGG)