65154 2026 eng 1 10 29 article Elsevier Ltd. Amsterdam, Niederlande 1 -- -- -- Oxide glasses are intrinsically brittle, lacking sufficient atomic-scale mechanisms that can relax mechanical stresses in the vicinity of a propagating crack. As a result, fracture is typically well-captured by considering local bond rupture at the crack tip. Here we demonstrate that barrier energies related to the low-temperature 𝛾-relaxation mode in alkali-aluminosilicate glasses are inversely related to the fracture toughness measured via standardized three-point bending fracture experiments. This holds true for both a series with varying cations (Li, Na, K) and one with varying Li concentration. The structural rationale for this finding is gained via Raman spectroscopy. The findings suggest that a fundamental structural relaxation mode measured on bulk specimens can serve as an effective guideline for fracture toughness of oxide glasses. Data for additional silicate glasses support this conclusion. Materials Today Advances 2590-0498 10.1016/j.mtadv.2025.100669 urn:nbn:de:kobv:b43-651540 true journal-article https://www.elsevier.com/tdm/userlicense/1.0/ crossref PersonAuthorFirstName_1,PersonAuthorLastName_1,PersonAuthorFirstName_2,PersonAuthorLastName_2,PersonAuthorFirstName_3,PersonAuthorLastName_3,PersonAuthorFirstName_4,PersonAuthorLastName_4,PersonAuthorFirstName_5,PersonAuthorLastName_5,PersonAuthorFirstName_6,PersonAuthorLastName_6,PersonAuthorFirstName_7,PersonAuthorLastName_7,PersonAuthorFirstName_8,PersonAuthorLastName_8,PersonAuthorFirstName_9,PersonAuthorLastName_9,PersonAuthorIdentifierOrcid_9,PublisherName,TitleMain_1,Language,TitleParent_1,ArticleNumber,Volume,PublishedYear,IdentifierIssn,Enrichmentlocal_crossrefLicence doi-import 19.01.2026 Creative Commons - CC BY - Namensnennung 4.0 International Marco Holzer Sidsel M. Johansen Johan F.S. Christensen Morten M. Smedskjaer Maria Rita Cicconi Dominique de Ligny Ralf Müller Andrea S.S. de Camargo Robert Maaß eng uncontrolled Fracture toughness eng uncontrolled Oxide glass eng uncontrolled Mechanical properties eng uncontrolled Alkali-aluminosilicate glasses eng uncontrolled Internal friction Ingenieurwissenschaften und zugeordnete Tätigkeiten 5 Werkstofftechnik 5.6 Glas Material Verlagsliteratur Datei für die Öffentlichkeit verfügbar ("Open Access") Wissenschaftliche Artikel der BAM 5.0 Abteilungsleitung und andere Materialdesign Bundesanstalt für Materialforschung und -prüfung (BAM) https://opus4.kobv.de/opus4-bam/files/65154/Direct con. betw. secondary relax. mode and fracture toughness in alkali-aluminosilicate glasses.pdf