{"id":{"repo_id":"trento","oai_identifier":"oai:iris.unitn.it:11572/489330"},"canonical_url":"https://search.dev.ndltd.org/etd/trento/oai:iris.unitn.it:11572/489330","repository":{"repo_id":"trento","name":"Università degli Studi di Trento","base_url":"https://iris.unitn.it/oai/request"},"display":{"title":"X-ray induced temperature dependent amorphous-amorphous transitions in the GeO2 glass","abstract":"Glasses are non-equilibrium materials whose structure and dynamics can be strongly modified by external perturbations such as ionizing radiation. This thesis investigates the effects of intense X-ray irradiation on vitreous germanium dioxide (v-GeO2), a prototypical strong oxide glass, by combining X-ray photon correlation spectroscopy (XPCS), X-ray diffraction (XRD), and inelastic X-ray scattering (IXS). The results demonstrate that intense X-rays induce atomic dynamics and structural transformations in v-GeO2 far below the glass transition temperature. The induced dynamics evolves with absorbed dose toward a stationary state whose properties depend on the irradiation temperature. Structural measurements reveal increased density fluctuations and reduced medium-range order, indicating a radiation-induced rejuvenation of the glass toward higher fictive-temperature states. To investigate these phenomena, novel XPCS data-analysis methodologies were developed, including the multi-tau two-time-correlation (MTTTC) approach and advanced detector corrections, enabling reliable measurements over extended timescales and low-signal conditions. Finally, the combination of XPCS and IXS measurements allows the non-ergodicity factor and density fluctuations to be studied across a broad frequency range, providing new insight into the microscopic mechanisms governing irradiation-induced amorphous-amorphous transitions in oxide glasses.","abstract_html":"Glasses are non-equilibrium materials whose structure and dynamics can be strongly modified by external perturbations such as ionizing radiation. This thesis investigates the effects of intense X-ray irradiation on vitreous germanium dioxide (v-GeO2), a prototypical strong oxide glass, by combining X-ray photon correlation spectroscopy (XPCS), X-ray diffraction (XRD), and inelastic X-ray scattering (IXS). The results demonstrate that intense X-rays induce atomic dynamics and structural transformations in v-GeO2 far below the glass transition temperature. The induced dynamics evolves with absorbed dose toward a stationary state whose properties depend on the irradiation temperature. Structural measurements reveal increased density fluctuations and reduced medium-range order, indicating a radiation-induced rejuvenation of the glass toward higher fictive-temperature states. To investigate these phenomena, novel XPCS data-analysis methodologies were developed, including the multi-tau two-time-correlation (MTTTC) approach and advanced detector corrections, enabling reliable measurements over extended timescales and low-signal conditions. Finally, the combination of XPCS and IXS measurements allows the non-ergodicity factor and density fluctuations to be studied across a broad frequency range, providing new insight into the microscopic mechanisms governing irradiation-induced amorphous-amorphous transitions in oxide glasses.","abstract_has_math":false,"creators":["Brugnara, Fabio"],"institution":"Università degli studi di Trento","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Zanatta, Marco","Baldi, Giacomo"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-06-11","date_published":"2026-06-11","updated_at":"2026-07-24T05:04:22Z","subjects":[],"languages":["eng"],"rights":["info:eu-repo/semantics/openAccess","license:Creative commons","license uri:http://creativecommons.org/licenses/by-nc-nd/4.0/"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/11572/489330","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Brugnara, Fabio","Zanatta, Marco","Baldi, Giacomo"]},{"key":"dc:creator","label":"Author","values":["Brugnara, Fabio"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2026-06-11"]},{"key":"dc:publisher","label":"Institution","values":["Università degli studi di Trento","place:TRENTO"]},{"key":"dc:relation","label":"Dc Relation","values":["firstpage:1","lastpage:177","numberofpages:177"]},{"key":"dc:type","label":"Dc Type","values":["info:eu-repo/semantics/doctoralThesis"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["info:eu-repo/semantics/openAccess","license:Creative commons","license uri:http://creativecommons.org/licenses/by-nc-nd/4.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/11572/489330"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Glasses are non-equilibrium materials whose structure and dynamics can be strongly modified by external perturbations such as ionizing radiation. This thesis investigates the effects of intense X-ray irradiation on vitreous germanium dioxide (v-GeO2), a prototypical strong oxide glass, by combining X-ray photon correlation spectroscopy (XPCS), X-ray diffraction (XRD), and inelastic X-ray scattering (IXS). The results demonstrate that intense X-rays induce atomic dynamics and structural transformations in v-GeO2 far below the glass transition temperature. The induced dynamics evolves with absorbed dose toward a stationary state whose properties depend on the irradiation temperature. Structural measurements reveal increased density fluctuations and reduced medium-range order, indicating a radiation-induced rejuvenation of the glass toward higher fictive-temperature states. To investigate these phenomena, novel XPCS data-analysis methodologies were developed, including the multi-tau two-time-correlation (MTTTC) approach and advanced detector corrections, enabling reliable measurements over extended timescales and low-signal conditions. Finally, the combination of XPCS and IXS measurements allows the non-ergodicity factor and density fluctuations to be studied across a broad frequency range, providing new insight into the microscopic mechanisms governing irradiation-induced amorphous-amorphous transitions in oxide glasses."]},{"key":"dc:title","label":"Title","values":["X-ray induced temperature dependent amorphous-amorphous transitions in the GeO2 glass"]}]}],"canonical_facts":{"dc:contributor":["Brugnara, Fabio","Zanatta, Marco","Baldi, Giacomo"],"dc:creator":["Brugnara, Fabio"],"dc:date":["2026-06-11"],"dc:description":["Glasses are non-equilibrium materials whose structure and dynamics can be strongly modified by external perturbations such as ionizing radiation. This thesis investigates the effects of intense X-ray irradiation on vitreous germanium dioxide (v-GeO2), a prototypical strong oxide glass, by combining X-ray photon correlation spectroscopy (XPCS), X-ray diffraction (XRD), and inelastic X-ray scattering (IXS). The results demonstrate that intense X-rays induce atomic dynamics and structural transformations in v-GeO2 far below the glass transition temperature. The induced dynamics evolves with absorbed dose toward a stationary state whose properties depend on the irradiation temperature. Structural measurements reveal increased density fluctuations and reduced medium-range order, indicating a radiation-induced rejuvenation of the glass toward higher fictive-temperature states. To investigate these phenomena, novel XPCS data-analysis methodologies were developed, including the multi-tau two-time-correlation (MTTTC) approach and advanced detector corrections, enabling reliable measurements over extended timescales and low-signal conditions. Finally, the combination of XPCS and IXS measurements allows the non-ergodicity factor and density fluctuations to be studied across a broad frequency range, providing new insight into the microscopic mechanisms governing irradiation-induced amorphous-amorphous transitions in oxide glasses."],"dc:identifier":["https://hdl.handle.net/11572/489330"],"dc:language":["eng"],"dc:publisher":["Università degli studi di Trento","place:TRENTO"],"dc:relation":["firstpage:1","lastpage:177","numberofpages:177"],"dc:rights":["info:eu-repo/semantics/openAccess","license:Creative commons","license uri:http://creativecommons.org/licenses/by-nc-nd/4.0/"],"dc:title":["X-ray induced temperature dependent amorphous-amorphous transitions in the GeO2 glass"],"dc:type":["info:eu-repo/semantics/doctoralThesis"]},"updated_at":"2026-07-24T05:04:22Z"}