{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/23864"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/23864","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The influence of structural relaxation upon the low-temperature thermal conductivity of ancient natural glasses","abstract":"It has been observed that the experimental low-temperature ( <lOK) properties of glasses depend upon a sample's thermal history. Apparently, the intrinsic glassy excitations (TLS) which dominate the low-temperature properties of glasses are affected by the structural relaxation which occurs in a glass sample in order to move that sample toward the equilibrium configuration for its current temperature. Investigations of structural relaxation in glasses show that relaxation processes involve a broad spectrum of relaxation rates and that the rates of the processes which prevail in a given experiment decrease dramatically with decreasing temperatures. Previous studies of low-temperature glassy properties on samples subjected to various thermal schedules have employed heat treatments at high temperatures, near or above the glass transition temperature, T g. for relatively short annealing periods ( <1 o-2 years). The present investigation studies relaxation behavior and its effects on the low-temperature TLS on the time scale of 1o4-107 years. These unusually long annealing times are made accessible to the laboratory by studying ancient natural glasses - amber, a fossil resin and obsidian, a volcanic glass - which have been annealed in the earth over geologic times. The low-temperature TLS behavior of the as-received glass was recorded via thermal conductivity, K, measurements (0.07K <T < 1 OK), and subsequently, the sample was heated above its T g and then quenched to change the structural state of the sample. K was measured again and compared to the as-received measurements. The obsidian K showed no significant change after heat treatment above T g· A possible explanation for this result could be the existence of a finite lower bound for the temperature range within which structural relaxation can occur. Such a temperature range is seen in polymers and the geologic annealing temperature for obsidian -o.3T g is outside the ranges commonly seen in polymers. The amber K showed a -5.6% reduction in magnitude after heat treatment above T g. similar to the results seen for metallic glasses annealed for -lQ-3 years. This suggests that the long-time relaxation processes which prevail in the amber experiment and the short-time relaxation processes which prevail in the glassy metal experiments have a common origin. At this time, no theoretical model appears to be able to explain the relationship between structural relaxation and the low-temperature TLS for all materials measured. Finally, if in fact 1Q6 years is a long enough annealing time for amber to reach its equilibrium configuration at 295K, then some minimum density of low-temperature TLS must be included in the equilibrium state of a glass.","abstract_html":"It has been observed that the experimental low-temperature ( &lt;lOK) properties of glasses depend upon a sample&#x27;s thermal history. Apparently, the intrinsic glassy excitations (TLS) which dominate the low-temperature properties of glasses are affected by the structural relaxation which occurs in a glass sample in order to move that sample toward the equilibrium configuration for its current temperature. Investigations of structural relaxation in glasses show that relaxation processes involve a broad spectrum of relaxation rates and that the rates of the processes which prevail in a given experiment decrease dramatically with decreasing temperatures. Previous studies of low-temperature glassy properties on samples subjected to various thermal schedules have employed heat treatments at high temperatures, near or above the glass transition temperature, T g. for relatively short annealing periods ( &lt;1 o-2 years). The present investigation studies relaxation behavior and its effects on the low-temperature TLS on the time scale of 1o4-107 years. These unusually long annealing times are made accessible to the laboratory by studying ancient natural glasses - amber, a fossil resin and obsidian, a volcanic glass - which have been annealed in the earth over geologic times. The low-temperature TLS behavior of the as-received glass was recorded via thermal conductivity, K, measurements (0.07K &lt;T &lt; 1 OK), and subsequently, the sample was heated above its T g and then quenched to change the structural state of the sample. K was measured again and compared to the as-received measurements. The obsidian K showed no significant change after heat treatment above T g· A possible explanation for this result could be the existence of a finite lower bound for the temperature range within which structural relaxation can occur. Such a temperature range is seen in polymers and the geologic annealing temperature for obsidian -o.3T g is outside the ranges commonly seen in polymers. The amber K showed a -5.6% reduction in magnitude after heat treatment above T g. similar to the results seen for metallic glasses annealed for -lQ-3 years. This suggests that the long-time relaxation processes which prevail in the amber experiment and the short-time relaxation processes which prevail in the glassy metal experiments have a common origin. At this time, no theoretical model appears to be able to explain the relationship between structural relaxation and the low-temperature TLS for all materials measured. Finally, if in fact 1Q6 years is a long enough annealing time for amber to reach its equilibrium configuration at 295K, then some minimum density of low-temperature TLS must be included in the equilibrium state of a glass.","abstract_has_math":false,"creators":["Love, Michela Suzanne"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Anderson, A.C."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-10T15:34:53Z","date_published":"2011-05-10T15:34:53Z","updated_at":"2026-07-22T22:25:22Z","subjects":["structural relaxation","low-temperature thermal conductivity","ancient natural glasses","intrinsic glassy excitations"],"languages":["en"],"rights":["Copyright 1991 Michela Suzanne Love"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["3478338"],"render_values":[{"text":"3478338","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/23864","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Anderson, A.C."]},{"key":"dc:creator","label":"Author","values":["Love, Michela Suzanne"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-10T15:34:53Z","10000-01-01","1991"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["structural relaxation","low-temperature thermal conductivity","ancient natural glasses","intrinsic glassy excitations"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1991 Michela Suzanne Love"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["3478338","http://hdl.handle.net/2142/23864"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["It has been observed that the experimental low-temperature ( <lOK) properties of glasses depend upon a sample's thermal history. Apparently, the intrinsic glassy excitations (TLS) which dominate the low-temperature properties of glasses are affected by the structural relaxation which occurs in a glass sample in order to move that sample toward the equilibrium configuration for its current temperature. Investigations of structural relaxation in glasses show that relaxation processes involve a broad spectrum of relaxation rates and that the rates of the processes which prevail in a given experiment decrease dramatically with decreasing temperatures. Previous studies of low-temperature glassy properties on samples subjected to various thermal schedules have employed heat treatments at high temperatures, near or above the glass transition temperature, T g. for relatively short annealing periods ( <1 o-2 years). The present investigation studies relaxation behavior and its effects on the low-temperature TLS on the time scale of 1o4-107 years. These unusually long annealing times are made accessible to the laboratory by studying ancient natural glasses - amber, a fossil resin and obsidian, a volcanic glass - which have been annealed in the earth over geologic times. The low-temperature TLS behavior of the as-received glass was recorded via thermal conductivity, K, measurements (0.07K <T < 1 OK), and subsequently, the sample was heated above its T g and then quenched to change the structural state of the sample. K was measured again and compared to the as-received measurements. The obsidian K showed no significant change after heat treatment above T g· A possible explanation for this result could be the existence of a finite lower bound for the temperature range within which structural relaxation can occur. Such a temperature range is seen in polymers and the geologic annealing temperature for obsidian -o.3T g is outside the ranges commonly seen in polymers. The amber K showed a -5.6% reduction in magnitude after heat treatment above T g. similar to the results seen for metallic glasses annealed for -lQ-3 years. This suggests that the long-time relaxation processes which prevail in the amber experiment and the short-time relaxation processes which prevail in the glassy metal experiments have a common origin. At this time, no theoretical model appears to be able to explain the relationship between structural relaxation and the low-temperature TLS for all materials measured. Finally, if in fact 1Q6 years is a long enough annealing time for amber to reach its equilibrium configuration at 295K, then some minimum density of low-temperature TLS must be included in the equilibrium state of a glass.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-10T15:34:53Z No. of bitstreams: 1 1991_Love.pdf: 1263547 bytes, checksum: 464bf988c9d3b00bf34657a9394c91aa (MD5)","Made available in DSpace on 2011-05-10T15:34:53Z (GMT). No. of bitstreams: 1 1991_Love.pdf: 1263547 bytes, checksum: 464bf988c9d3b00bf34657a9394c91aa (MD5) Previous issue date: 1991","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-05-10T15:34:53Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:13:25-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["The influence of structural relaxation upon the low-temperature thermal conductivity of ancient natural glasses"]}]}],"canonical_facts":{"dc:contributor":["Anderson, A.C."],"dc:creator":["Love, Michela Suzanne"],"dc:date":["2011-05-10T15:34:53Z","10000-01-01","1991"],"dc:description":["It has been observed that the experimental low-temperature ( <lOK) properties of glasses depend upon a sample's thermal history. Apparently, the intrinsic glassy excitations (TLS) which dominate the low-temperature properties of glasses are affected by the structural relaxation which occurs in a glass sample in order to move that sample toward the equilibrium configuration for its current temperature. Investigations of structural relaxation in glasses show that relaxation processes involve a broad spectrum of relaxation rates and that the rates of the processes which prevail in a given experiment decrease dramatically with decreasing temperatures. Previous studies of low-temperature glassy properties on samples subjected to various thermal schedules have employed heat treatments at high temperatures, near or above the glass transition temperature, T g. for relatively short annealing periods ( <1 o-2 years). The present investigation studies relaxation behavior and its effects on the low-temperature TLS on the time scale of 1o4-107 years. These unusually long annealing times are made accessible to the laboratory by studying ancient natural glasses - amber, a fossil resin and obsidian, a volcanic glass - which have been annealed in the earth over geologic times. The low-temperature TLS behavior of the as-received glass was recorded via thermal conductivity, K, measurements (0.07K <T < 1 OK), and subsequently, the sample was heated above its T g and then quenched to change the structural state of the sample. K was measured again and compared to the as-received measurements. The obsidian K showed no significant change after heat treatment above T g· A possible explanation for this result could be the existence of a finite lower bound for the temperature range within which structural relaxation can occur. Such a temperature range is seen in polymers and the geologic annealing temperature for obsidian -o.3T g is outside the ranges commonly seen in polymers. The amber K showed a -5.6% reduction in magnitude after heat treatment above T g. similar to the results seen for metallic glasses annealed for -lQ-3 years. This suggests that the long-time relaxation processes which prevail in the amber experiment and the short-time relaxation processes which prevail in the glassy metal experiments have a common origin. At this time, no theoretical model appears to be able to explain the relationship between structural relaxation and the low-temperature TLS for all materials measured. Finally, if in fact 1Q6 years is a long enough annealing time for amber to reach its equilibrium configuration at 295K, then some minimum density of low-temperature TLS must be included in the equilibrium state of a glass.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-10T15:34:53Z No. of bitstreams: 1 1991_Love.pdf: 1263547 bytes, checksum: 464bf988c9d3b00bf34657a9394c91aa (MD5)","Made available in DSpace on 2011-05-10T15:34:53Z (GMT). No. of bitstreams: 1 1991_Love.pdf: 1263547 bytes, checksum: 464bf988c9d3b00bf34657a9394c91aa (MD5) Previous issue date: 1991","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-05-10T15:34:53Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:13:25-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"],"dc:identifier":["3478338","http://hdl.handle.net/2142/23864"],"dc:language":["en"],"dc:rights":["Copyright 1991 Michela Suzanne Love"],"dc:subject":["structural relaxation","low-temperature thermal conductivity","ancient natural glasses","intrinsic glassy excitations"],"dc:title":["The influence of structural relaxation upon the low-temperature thermal conductivity of ancient natural glasses"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:22Z"}